1 Results The findings of the Study Two are reported in four sections. The first section presents the preliminary analysis of the data. This includes screening for missing values, univariate and mulitvariate outliers, normality and examination of relationships between variables. The reliability analyses of the scales are then presented. In the second section, the participants' characteristics are analysed. The third and fourth section analyse the hypotheses of the study. The third section presents analyses of the proposed model. In the fourth section analyses based on the adaptive outcomes of primary and secondary control are presented. Data were analysed using SPSS Window’s version 10.0 program. Preliminary Analyses Each variable was screened for missing data, normality and univariate and multivariate outliers for each of the three groups, that is, people with MS, partners, and controls. The relationships between variables were also explored and the scales were tested for reliability within the three groups. The data were screened for missing values using the FREQUENCIES option in SPSS. A small number of missing values were identified, which appeared to be scattered randomly. Group means were calculated based on the available data and used to replace the missing values as recommended by Tabachnick and Fidell (1996). Univariate outliers were identified through box plots and stem and leaf diagrams generated using the EXPLORE option in SPSS. A small number of outliers were identified. In accordance with the method recommended by Tabachnick and Fidell (1996), univariate outliers were assigned a raw score on the offending variable that was one unit larger or smaller than the next most extreme score. Multivariate outliers were identified using Mahalnobis Distance with p < .001. One multivariate outlier was detected and deleted from subsequent analysis. 2 The data were screened for normality using the EXPLORE option in SPSS. The variables were screened for the three groups using measures of skewness, kurtosis, histograms, the Kolmogorov-Smirnov statistic and the Shapiro-Wilk statistic. Skewness and kurtosis were not extreme. However, moderate skewness was associated with some measures. The histograms of the variables similarly indicated normal distributions for most variables, with skewness for some. The Kolmogrov-Smirnov statistic was calculated for people with MS and the control group. The Shapiro-Wilk statistic was calculated for partners as the group comprised less than fifty participants (Coakes & Steed, 1999). These statistics were significant for most of the variables for the three groups reflecting normal distributions. The statistics demonstrated that none of the variables were sufficiently non-normal to compromise the subsequent analysis. Correlation matrices were generated to explore relationships among the variables for each group. These matrices are shown in Table 8.1 to 8.3. The Pearson correlation co-efficient was calculated for controls and people with MS. Spearman Rho’s coefficient was calculated for partners as recommended by Coakes and Steed (1999) due to the small sample size. The correlation matrix revealed that no variables were highly inter-correlated (above 0.9), thus, there was no evidence of singularity. Some variables were inter-correlated at 0.7 and above, these variables were closely monitored when included together in further analyses as highly inter-correlated variables inflate the size of error terms and weaken an analysis (Tabachnick & Fidell, 1996). Scatterplots indicated that the variables were linearly and homoscedastically interrelated. In summary, most of the variables were normally distributed for the three groups. Some of the variables mildly deviated from normality, however, transformation was not undertaken for two reasons. Firstly, none of the variables markedly deviated from normality for all three groups. Secondly, some skewness was considered to reflect the inherent nature of the variables and the groups. Thirdly, all of the scales are meaningful and widely used, and some of the scales are standardized. Tabachnick and Fiddel (1996) recommend against transformation of such scales as it often hinders interpretation. Table 8.1 Pearson Correlations between Variables for Controls Personality Variables Neuroticism Extraversion Self-protective Situation bias Avoidant Self-affirmative Ventilation Primary Control Self-esteem Optimism From people From pets Subjective Quality of Life Neuroticism 1.00 -.26* .24* -.12 .27* .12 .48** -.13 -.73** -.53** -.09 .13 -.50** Secondary Control Extraversion 1.00 -.17 .22* -.16 .22* -.20 .18 .40* .37** .46** .01 .27* Selfprotective Situation bias 1.00 .36** .46** .47** .25* .32* -.24* -.11 -.12 -.18 -.15 1.00 .23 .47** -.03 .68** .15 .37** .28* -.06 .02 Avoidant 1.00 .40** .21* .12 -.36** -.11 -.10 -.01 -.19 Positive Cognitive Bias Selfaffirmative 1.00 .28* .45** -.04 .06 .46** -.05 -.01 Ventilation 1.00 .06 -.33* -.39** .04 .02 -.29* Primary Control Selfesteem 1.00 .16 .26* .18 -.13 .06 1.00 .56** .29* -.04 .60** Optimism 1.00 .27* -.04 .50** Perceived Social Support From From people pets 1.00 .08 .38** 1.00 .05 Subjective Quality of Life 1.00 Two tailed correlations * p < .05, ** p < .001, n=93 3 Table 8.2 Pearson Correlations between Variables for People with MS Personality Variables Neuroticism Extraversion Self-protective Situation bias Avoidant Self-affirmative Ventilation Primary Control Self-esteem Optimism From people From pets Subjective Quality of Life Neuroticism 1.00 -.48** .03 -.14 .21 -.05 .46** -.13 -.80** -.58** -.33* -.17 -.60** Extraversion 1.00 -.25 .13 -.35* .08 .02 .06 .51** .60** .09 .01 .35* Secondary Control Selfprotective 1.00 .34* .35* .29* -.08 .26* -.16 -.05 -.10 .01 -.11 Situation bias 1.00 .25* .58** -.12 .78** .09 .26* .01 .04 -.12 Avoidant 1.00 .21 -.29* .18 -.25* -.31* -.20 -.09 -.27* Positive Cognitive Bias Selfaffirmative 1.00 -.12 .48** .07 .19 -.03 .17 -.05 Ventilation 1.00 -.14 -.43** -.25 -.17 -.09 -.38* Primary Control Selfesteem 1.00 .01 .23 -.09 -.01 -.15 1.00 .64** .48** .22 .68** Optimism 1.00 .23 .15 .50** Perceived Social Support From From people pets 1.00 .09 .53** 1.00 .25* Subjective Quality of Life 1.00 Two tailed correlations * p < .05, ** p < .001, n=65 4 Table 8.3 Spearman Correlations between Variables for Partners Personality Variables Neuroticism Neuroticism Extraversion Self-protective Situation bias Avoidant Self-affirmative Ventilation Primary Control Self-esteem Optimism From people From pets Subjective Quality of Life 1.00 -.23 .25 -.34* .23 .17 .28 -.21 -.76** -.52* -.35* -.21 -.48* Extraversion 1.00 .09 .34* .10 .14 -.06 .33* .28 .38* .23 -.14 .28 Secondary Control Selfprotective 1.00 .29 .44* .35* .12 .25 -.36* -.03 .07 -.22 -.02 Situation bias 1.00 .18 .38* .15 .82** .31 .32 .26 .19 .50* Avoidant 1.00 .21 -.10 .01 -.31 -.03 -.05 -.16 -.19 Selfaffirmative 1.00 .18 .29 -.09 -.24 .19 -.04 .14 Positive Cognitive Bias Ventilation 1.00 .16 -.34* -.20 -.29 -.10 -.26 Primary Control 1.00 .23 .25 .16 .11 .43* Self-esteem 1.00 .54* .50* .25 .56** Optimism 1.00 .48* .30 .48* Perceived Social Support From From pets people 1.00 .42* .59** 1.00 .44* Subjective Quality of Life 1.00 Two tailed correlations * p < .05, ** p < .001, n=37 5 6 Scale Reliabilities Although the scales of the study are widely used, it was necessary to confirm the reliability of the scales for use with a clinical sample, namely people with MS and partners. Based on the findings of Study One items were added to the Comprehensive Quality of Life Scale, the Primary and Secondary Control Scale, and the Perceived Social Support Scale. Other items in the Rosenberg SelfEsteem Inventory and the Extraversion subscale of the NEO Five-Factor Inventory were identified as potentially biased towards people with MS. Reliability analyses of the scales with the new items added were carried out using Cronbach’s alpha criterion (). These are shown in Table 8.4. Cronbach’s alpha ranges from .66 to .93. All of the scales had excellent reliability for the three groups with the exception of the Secondary Control subscale for partners, the Extraversion subscale for partners and the Importance subscale of the ComQol for people with MS which all had moderate reliability (Tabacknick & Fidell, 1986). In summary, the scales were reliable for the three comparison groups. Table 8.4 Reliability Analyses of the Scales People with MS Controls (n = 65) Partners of People with MS (n = 37) Scale (n = 93) Primary and Secondary Control Subscales Primary Control Secondary Control .76 .71 .72 .69 .75 .84 NEO Five Factor Inventory Subscales Neuroticism Extraversion .86 .79 .83 .68 .89 .79 ComQOL Subscales Importance Satisfaction .66 .84 .83 .88 .74 .84 Rosenberg Self-Esteem Scale .90 .81 .86 Life Orientation Test .84 .86 .83 Perceived Social Support Subscales From people From pets .88 .93 .88 .80 .85 .86 7 Reliability Analysis of the Primary and Secondary Control Scale Two new items were added to the Primary and Secondary Control Scale based on the findings of Study One. These were item seventeen: ‘when I have difficulty doing something I give up’ and item eighteen: ‘when I have difficulty doing something I yell, scream, or cry’. A reliability analysis was undertaken to confirm the reliability of these new items. This is presented in Table 8.5. Table 8.5 Reliability Analysis of the Primary and Secondary Control Scale Item People with MS (n= 65) Corrected Alpha if Item-Total Item Correlation Deleted Partners (n=37) Corrected Alpha if Item-Total Item Correlation Deleted 1. SC .48 .76 2. SC .44 .76 3. PC .65 .75 4. SC .47 .76 5. SC .31 .77 6. SC .58 .75 7. PC .20 .78 8. SC .06 .79 9. PC .41 .76 10. SC .13 .79 11. SC .43 .76 12. SC .39 .77 13. SC .22 .78 14. SC .59 .75 15. PC .56 .76 16. SC .56 .76 17. NEW .12 .78 18. NEW -.17 .80 Total scale .78 alpha NEW = New item based on study 1 findings PC = Primary control item SC = Secondary control item .35 .29 .50 .41 .23 .44 .29 .46 .35 .29 .41 .40 .00 .44 .51 .62 .13 .17 .76 .76 .75 .75 .77 .75 .76 .75 .76 .76 .75 .75 .78 .75 .74 .73 .78 .77 .77 Controls (n=65) Corrected Alpha if Item-Total Item Correlation Deleted .41 .48 .44 .44 .39 .56 .43 .45 .44 .59 .46 .60 .29 .50 .48 .56 .33 .21 .84 .84 .84 .84 .84 .84 .84 .84 .84 .83 .84 .83 .85 .84 .84 .84 .85 .85 .85 Most of the items of the scale, including the new items, contributed to the reliability of the scale. None of the items contributed significantly with decreased reliability. One of the new items, number eighteen, was associated with decreased reliability for people with MS only. This item was also negatively correlated with the other items of the scale for people with MS only. Thus, the inclusion of the new items and the reliability of the scale were confirmed. 8 Factor Analysis of Primary and Secondary Control Scale A factor analysis was conducted on the new version of the Primary and Secondary Control Scale to determine the validity of the factors of the scale including the two new items. The authors of the scale recommend five factors: primary control, and four types of secondary control: situation bias, self-protective, self-affirmative and avoidant (Maher et al, 2000). They claim that primary control and the four types of secondary control each serve a different purpose and as such, they do not expect these factors to emerge from a factor analysis. A principal components factor analysis was conducted on the entire sample (n = 194), including an oblique rotation of the solution in order to aid the interpretation of the factors. Table 8.6 shows the oblique rotation analysis. The analysis produced four factors that closely resembled the factors of the scale. Few items loaded on more than one factor. Primary control, situation bias and one selfprotective item loaded onto one factor. The remaining self-protective items loaded onto the second factor. Self-affirmative items loaded onto the third factor. Avoidant items loaded on the fourth factor. The other new item ‘give up’ loaded with the avoidant secondary control items of the scale. This is inconsistent with the proposition of the first study that this item would load with primary control items as it reflects perceptions of primary control. The other new item, ‘ventilation’, failed to load on any of the factors. However, it was retained for further analysis. As discussed in study one, ventilation was frequently mentioned as a way to cope with stressors. Following from this and the factor analysis, it was proposed that ventilation may represent a type of secondary control not before recognised. Thus, the item was analysed separately from the other factors of the scale. 9 Table 8.6 Factor Analysis of the Primary and Secondary Control Scale Items 15. Primary control 9. Primary control 7. Primary control 3. Primary control 16. Situation bias 14. .Situation bias 1. Self-protective 4. Self-protective 5. Self-protective 2. Self-protective 6. Self-affirmative 10. Self-affirmative 8. Self-affirmative 11. Self-affirmative 13. Avoidance 12. Avoidance 17. New item 18. New item Factor 1 .81 .79 .72 .70 .67 .59 .52 Factor 2 Factor 3 Factor 4 .30 .83 .80 .66 .36 .39 .78 .75 .56 .32 -.76 -.76 .60 n = 195 In summary, the factor analysis confirmed the factor structure of control. In further analysis, the new item ‘give up’ was categorised with the avoidant secondary control items. The other new item, ‘Ventilation’ was analysed separately. Factor 1 was split into primary control and situation bias, to reflect their divergent purposes. Thus, the scale items comprised five factors based on the hypothesised purpose of the items. Analysis of the Domains of the ComQol The life domain ‘independence’ was added to the ComQol based on the findings of the first study. A reliability analysis was conducted to determine the reliability of the scale with the new life domain. This is shown in Table 8.7. The independence domain contributed to the reliability of the scale across the three groups. Thus, the new ComQol scale was reliable for all three groups. 10 Table 8.7 Reliability Analysis of Comprehensive Quality of Life Scale Domain Importance Possesions Health Achievment Intimacy Safety Community Happiness Independence* Total Alpha Satisfaction Possesions Health Achievment Intimacy Safety Community Happiness Independence* Total Alpha People with MS (n= 65) Corrected Alpha if Item-Total Item Correlation Deleted Partners (n=37) Corrected Alpha if Item-Total Item Correlation Deleted Controls (n=65) Corrected Alpha if Item-Total Item Correlation Deleted .24 .33 .53 .42 .29 .22 .33 .40 .63 .61 .54 .58 .61 .64 .60 .60 .66 .24 .50 .42 .56 .74 .57 .78 .65 .85 .80 .81 .79 .76 .79 .76 .78 .83 .51 .41 .50 .41 .46 .51 .42 .26 .70 .72 .70 .72 .71 .69 .72 .75 .74 .61 .56 .55 .69 .63 .43 .70 .44 .82 .83 .83 .81 .82 .84 .81 .84 .84 .55 .55 .70 .75 .62 .36 .81 .77 .87 .87 .56 .85 .87 .89 .84 .85 .88 .42 .53 .58 .56 .58 .57 .75 .61 .84. .83 .82 .82 .82 .82 .80 .82 .84 * new life domain based on Study One findings Potentially Sensitive Items of the NEO Five-Factor Inventory and the Rosenberg Self-Esteem Inventory Study One identified that some items of the questionnaire that might be unduly sensitive to people with MS. These included three items of the extraversion subscale of the NEO Five Factor Inventory namely: "I often feel as if I am bursting with energy', 'My life is fast-paced' and 'I am a very active person'. These items may be confounded by symptoms of MS, and may measure illness rather than personality. A two-way ANOVA was conducted to compare the differences between the three groups on the total extraversion score and on an extraversion score without the three potentially biased items. This was undertaken to determine whether differences on the subscale between people with MS and the other two groups were unduly influenced by the three items. Box’s M was not significant at p > .001, thus indicating that the data was suitable for the analysis. The Pillai’s criterion revealed a significant overall effect of group, 11 F (20, 191) = 7.15, p < .001, ² = .07, p= .99. Post hoc univariate tests revealed that people with MS were significantly less extraverted than controls on the total extraversion (p < .001). However, they were no different from the other two groups on the extraversion score with sensitive items removed. Thus, the differences between the groups on the extraversion measure are attributable to the three identified items, which likely measure MS symptoms rather than personality. A reliability analysis was conducted using Cronbach’s alpha () to determine whether removal of the items from the scale would detrimentally effect the reliability of the scale. The reliability of the extraversion subscale with and without the sensitive items is shown in Table 8.8. Table 8.8. Reliability Analysis of the Extraversion Subscale With and Without Sensitive Items Scale Total Scale Scale with Sensitive Items Removed People with MS (n = 65) .79 .74 Partners of People with MS (n = 37) .68 .69 Controls (n = 93) .79 .77 The reliability of the scales was not significantly reduced due to the removal of the three items. Therefore these items were omitted from further analysis for all three groups. The first study also identified one item in the Rosenberg Self-Esteem Scale as potentially sensitive to people with MS namely: ‘I am unable to do things as well as other people’. A two-way ANOVA was conducted as described above to determine the validity of these items for the three groups. The three groups differed significantly on self-esteem, despite removal of the potentially sensitive item. Thus, this item was retained for further analysis. 12 Summary of the Preliminary Analyses Analyses revealed that the data did not significantly deviate from normality. Some deviations were apparent, however these were deemed to be minimal, not common to all three groups, and an inherent nature of the sample. Thus, data transformation was not undertaken. Some outliers were present. These were either re-coded or deleted from subsequent analyses. The reliability and factor structure of the scales, including the new items, were confirmed. Thus, the new items proposed in study one were retained in the analysis of data in study two. Three items of the extraversion scale were removed from further analyses, as it was likely that these items were biased towards people with MS. The domains of the ComQol and the domains differently contributed to self-esteem. Analysis of Participant Characteristics Table 8.9 describes the sample in terms of age, gender, years in current relationship, and living arrangement with partner. Two-thirds of the people with MS were female. Consistent with this, one third of partners were female. This is consistent with estimates of the gender ration of the prevalence of MS in the general population (MS Society Australia, 2000). In contrast, approximately half of the controls were female. Almost all the sample lived with their partners. Table 8.9 Participant Demographic Characteristics People with MS Controls (n = 65) Partners of People with MS (n = 37) 49.92 10.13 49.22 10.22 43.12 13.55 21 (32.8%) 43 (67.2%) 24 (64.9%) 13 (35.1%) 44 (47.3%) 49 (49.0%) 20.64 12.94 22.35 13.23 17.01 13.40 59 (92.2%) 34(91.9%) 78 (83.9%) Characteristic Age (years) Mean SD Gender Male Female Length of Relationship (years) Mean SD Live with Partner (yes or no) (n = 93) 13 Table 8.10 describes the illness characteristics of the sample. Table 8.10 Participant Illness Characteristics People with MS (n = 65) Partners (n = 37) (responses refer to partner’s MS) 38 (59.4%) 17 (26.6%) 3 (4.7%) 1 (1.6%) 2 (3.1) 15 (40.5%) 15 (40.5%) 1 (2.7%) 3 (8.1%) 3 (8.1%) First diagnosed with MS (years ago) Mean SD 8.55 8.03 8.62 7.28 Onset of MS (years ago) Mean SD 13.51 8.92 10.06 7.57 Disabled by MS (1 fully independent – 10 fully dependent on others) Mean SD. 3.69 2.60 4.43 2.63 Change in MS in last year (1 = deteriorated – 10 improved) Mean SD 4.93 2.15 4.70 1.81 6.05 1.99 5.69 1.67 5.67 2.85 6.00 2.90 N/A 4.13 2.39 41 (64.1%) N/A Characteristic Type of MS Relapsing-remitting Progressive Secondary progressive Stable Other Compared to average state (1 much worse – 10 much better) Mean SD Effect of MS on life role (1 does not effect – 10 prevents from performing role would like) Mean SD Effect of MS on partner’s Life role (1 does not effect – 10 prevents from performing role would like) Mean SD Experience pain through MS (yes or no) The relative prevalence of the different types of MS evident in the sample was consistent with estimates of the general population. As discussed in Chapter 2, 50 to 60% of people with MS in the general population have Relapsing-Remitting 14 MS, 10 to 20% have either Primary Progressive MS (or chronic progressive) or Secondary Progressive MS and 20 to 30% have Benign MS (Rao et al, 1992). Participants rated their current state as slightly better than their average state, and reported only a slight deterioration in the last year. These data suggest that most participants were in a period of illness remission rather than exacerbation at the time of the study. There was a large variation in time since diagnosis and onset of MS. People with MS were not fully independent on average, and rated themselves as minimally dependent on others for care. People with MS on average reported that their illness had moderately prevented them from performing the role in life they would like to. Most people with MS experienced pain through MS. Partners of people with MS rated their partners’ illness similarly, however their partner’s MS effected their life role to a lesser extent. The Proposed Model for the Maintenance of Subjective Quality of Life A model was previously discussed that explains the mechanism by which subjective quality of life is maintained in an adaptive range. It was hypothesised that personality, positive cognitive bias of self-esteem, control, and optimism, personality predict a significant proportion of subjective quality of life evaluations, which differs between people with MS, partners, and controls and that secondary control mediates between positive cognitive biases and subjective quality of life. The model was shown previously, and is shown again in Figure 8.3. 15 FIRST ORDER DETERMINANTS: Personality SECOND ORDER DETERMINANTS: Internal Buffers THIRD ORDER MEDIATING DETERMINANT Perceived Social Support Extraversion Neuroticism Positive Cognitive Biases Self-Esteem Optimism Primary Control Secondary Control Subjective Quality of Life Environmental Factors Figure 8.3 The proposed model for the maintenance of subjective quality of life Unfortunately the relatively small sample size precluded the analysis of this model through structural equation modeling (Tabachnick & Fidell, 1996). This model was tested through a range of MANOVAs, ANOVAs, and REGRESSION analyses. However, the shortcoming of this approach is that the proposed model cannot be tested in its entirety and the risk of Type I errors increases. A figure of the model is presented prior to each section with the parts of the model to be analysed highlighted. Differences between the Groups Hypotheses one, four and five predicted differences between the groups in the variables of the model. These hypotheses stated: 16 Hypothesis 1: People with MS have the lowest subjective quality of life. Partners have a higher, and controls the highest subjective quality of life. Hypothesis 4: Positive cognitive biases of primary control and selfesteem are smaller for people with MS than partners and controls. Hypothesis 5: Positive cognitive biases of optimism are larger for people with MS than partners and controls. A MANOVA was conducted to analyse differences between the groups on all of the variables of the model. Box’s M indicated that the test of homogeneity of variance had not been violated at an alpha level of .05. With the use of the Pillai’s Trace criterion the combined dependent variables were significantly effected by group membership, F(30, 356) = 4.03, p < .001. Table 8.11 shows the means (X), standard deviations (SD), significance (F), power and strength of associations (²) for each group. The mean and standard deviation are presented as a percentage of the scale maximum, where appropriate, for ease of comparison. 17 Table 8.11 Multivariate Analysis of the Variables of the Model by Group Variables Age (years) X SD Length of relationship(years) X SD Subjective Quality of Life X SD Personality Neuroticism X SD Extraversion X SD Positive Cognitive Bias Self-esteem X SD Optimism X SD Control X SD Perceived Social Support People X SD Pets X SD Secondary Control Self-Protective X SD Situation Bias X SD Avoidant X SD Self-Affirmative X SD Ventilation X SD People with MS (n=64) Partners Controls (n = 37) (n=93) 46.92 10.13 49.22 10.22 20.64 12.94 F power ² 43.12 13.55 4.11* .72 .04 22.35 13.22 17.01 13.40 2.70 .53 .03 66.81 15.35 76.26 12.91 76.57 10.42 12.45** .99 .12 44.46 22.37 37.54 14.71 40.41 17.44 .79 .18 .01 42.22 12.98 43.50 9.26 45.13 9.87 1.73 .36 .02 66.84 20.41 75.55 13.04 76.71 12.71 7.96** .95 .08 65.93 23.64 75.53 15.91 71.92 17.32 1.81 .38 .02 66.68 16.81 61.79 17.57 64.21 14.26 2.44 .49 .03 75.96 18.53 67.07 20.67 75.03 19.29 7.63* .94 .07 68.72 28.13 80.26 18.93 68.39 25.73 1.98 .41 .02 53.56 16.57 46.15 13.14 46.14 12.76 2.67 .53 .03 66.57 19.92 64.25 18.99 64.51 18.53 1.22 .26 .01 36.64 12.99 33.40 12.49 31.54 10.35 4.00* .71 .04 53.70 14.28 51.96 18.35 55.65 15.39 2.88 .56 .03 41.25 22.37 37.69 20.65 37.14 21.98 .34 .10 .01 * p < .05, ** p < .001, n = 194, ² = strength of association 18 Table 8.11 (continued) Multivariate Analysis of the Variables of the Model by Group People with MS ComQol Domains Satisfaction: Possessions X SD Health X SD Achievements X SD Intimacy X SD Safety X SD Community X SD Happiness X SD Independence X SD Importance: Possessions X SD Health X SD Achievements X SD Intimacy X SD Safety X SD Community X SD Happiness X SD Independence X SD Partners of People with MS Controls 78.78 21.75 81.57 17.60 76.29 15.32 49.78 20.19 76.90 18.00 64.49 20.98 Power ² 1.19 .26 .01 76.88 16.09 49.22* 1.00 .34 72.73 18.05 75.20 15.21 7.00* .92 .07 76.91 22.93 82.84 17.75 82.02 12.92 1.98 .41 .02 75.80 19.18 83.59 19.18 82.71 12.78 4.63* .78 .05 70.40 19.79 74.75 14.35 74.51 16.64 1.24 .27 .01 71.43 23.53 75.76 18.01 79.65 15.43 3.58* .66 .04 68.77 22.06 76.27 18.29 79.74 15.18 6.87* .92 .07 64.04 21.12 64.32 23.75 68.37 18.84 1.02 .27 .01 89.68 13.80 90.81 14.79 89.89 12.38 .09 .06 .34 79.20 19.86 79.19 19.20 78.37 15.90 .05 .06 .07 92.79 15.75 90.27 14.43 88.15 14.44 1.84 .38 .02 83.85 19.93 81.62 19.22 81.85 17.50 .27 .09 .05 67.40 22.23 65.68 21.80 65.43 18.38 .19 .08 .01 87.88 19.53 82.49 17.06 85.11 13.95 1.30 .28 .04 89.84 12.02 85.14 17.42 81.20 17.87 5.49* .85 .07 F * p <.05, ** p <.001, n = 194, ² = strength of association 19 The analysis revealed a significant effect of group for age, subjective quality of life, self-esteem, perceived social support from people, avoidant secondary control, satisfaction with the life domains of health, achievements, safety, happiness, independence, and importance of the independence life domain. Univariate tests revealed that partners were significantly older than controls,. Consistent with hypothesis one, people with MS reported a lower subjective quality of life than partners and controls, F(2,194) = 12.45, p < .001. Consistent with hypothesis four, they also reported lower self-esteem than both partners (p < .05) and controls (p < .001) In contrast with hypothesis four and five, partners did not differ from controls in the magnitude of their positive cognitive biases, and there was no difference between the three groups in positive cognitive biases of optimism. Partners reported lower perceived social support than both people with MS (p < .05) and controls (p < .05). People with MS also reported more avoidant secondary control than controls (p < .05). In regards to the domains of the ComQol, people with MS were less satisfied with their health than both partners and controls (p < .001). They were also less satisfied with what they had achieved than controls (p < .05). They were less satisfied with how safe they felt than both partners and controls (p < .05), and less satisfied with their happiness than controls (p < .05). Although people with MS rated their independence as significantly more important than controls (p < .05), they were significantly less satisfied with their independence than controls (p < .05). The power of these tests were mostly moderate to excellent (.99). However, the strength of associations were low (.02 to .12). Most participants classified their or their partner’s diagnosis as either ‘relapsingremitting’ or ‘progressive’. A minority of participants reported a different diagnosis including ‘stable’ and ‘benign’. Due to the small numbers that reported other types of MS, only relapsing-remitting and progressive MS could be compared. Table 8.12 shows the means, and standard deviations of subjective quality of life for the three groups as a percentage of the scale maximum. The total number of participants reported in the tables is more than the sum of participants reporting relapsing-remitting MS or progressive MS as it includes those that 20 reported other types of MS. There was no difference in the subjective quality of life of the different types of MS (i.e. progressive or relapsing-remitting) as evidenced by a t-test. Thus, further analyses treated the group as a homogenous sample of people with MS. Table 8.12 The Subjective Quality of Life of Each Group and Illness Type Group and illness type People with MS Relapsing-Remitting, n = 38 X SD Progressive, n = 17 X SD Total, n = 64 X SD Partners of People with MS Relapsing-Remitting, n = 15 X SD Progressive, n = 15 X SD Total, n = 37 X SD Controls, n = 93 X SD Subjective quality of life 68.41 15.53 64.28 16.27 66.81 15.35 77.58 13.22 75.03 12.31 76.26 12.91 76.57 10.42 Interactions between Variables Hypotheses two and three, below, predicted interactions between variables of the model: Hypothesis 2: Perceived social support and positive cognitive bias predict subjective quality of life after personality has been controlled. Hypothesis 3: Secondary control mediates between positive cognitive biases and secondary control. 21 Hypothesis 2 was tested using a Hierarchical regression analyses for each group. This analysis is represented by the bold lines in Figure 8.4. FIRST ORDER DETERMINANTS: Personality SECOND ORDER DETERMINANTS: Internal Buffers THIRD ORDER MEDIATING DETERMINANT Perceived Social Support Extraversion Neuroticism Positive Cognitive Biases Self-Esteem Optimism Primary Control Subjective Quality of Life Secondary Control Environmental Factors Figure 8.4 Analysis of Hypothesis 2: Interactions between Variables of the Model Personality, perceived social support, the three positive cognitive biases, secondary control and illness variables were entered in four steps of a hierarchical regression analysis for each group. Further hypotheses regarding specific interactions between variables, including the mediating role of secondary control, the threshold effect of perceived social support, and the adaptive outcome of primary and secondary control, were then examined through further multiple regressions, ANOVAs, and MANOVAs. The correlation matrices in Tables 8.1 to 8.3 were examined for evidence of multicollinearity and singularity. Self-esteem was highly correlated with both the 22 subjective quality of life of the three groups (r2 = .60, p < .001 for controls, r2 = .68, p < .05 for people with MS, r2 = .56, p < .001 for partners) and with neuroticism (r2 = -.73, p < .001 for controls, r2 = -.80, p < .001 for people with MS, r2 =-.76, p < .001 for partners). As discussed previously, the inclusion of highly inter-correlated variables weakens statistical analyses (Tabachnick & Fidell, 1986). Thus, self-esteem was closely monitored and the analyses were conducted both with and without this variable to ensure that it was not negatively effecting the regression. Variables were entered into steps of the regression based on the order hypothesised by the model. Specifically, extraversion and neuroticism were entered into the first step as these were hypothesised to exert the strongest influence on subjective quality of life. Positive cognitive bias and perceived social support were entered into the next step. In the third step, the five types of secondary control were added. In the final step, two illness related variables were added for people with MS and partners to determine whether MS exerted an influence on subjective quality of life once psychological factors were controlled for. With up to nine variables in the regression equation, the ratio of cases to independent variables was sufficient for both controls and people with MS. However, the ratio was less than the minimum five to one ratio recommended by Coakes and Steed (1999) for partners. Using this ratio, the maximum number of variables in the equation for partners is seven. Thus, the number of variables in the last two steps of the analysis for partners exceeds this number and should be interpreted with caution. Preliminary regression analyses were conducted with the original extraversion score, and then with the extraversion score without the three sensitive items identified in study. There was no significant difference between the two analyses for people with MS and partners. However, for the control group while the original extraversion score was a significant predictor of subjective quality of life in the regression analyses, the newly comprised score without the three items was 23 not. The two regression analyses of personality and subjective quality of life for the control group are shown in Table 8.13 Table 8.13 Regression Analyses of the Effect of the Two Extraversion Scores on the Subjective Quality of Life of Controls Variables in the equation Regression Analysis 1 Original Extraversion Score Neuroticism R = .53, R2 = .28 Adjusted R2 = .27 Standard error = 71.44 F(2,90) = 17.63* Regression Analysis 2 New Extraversion Score Neuroticism R = .52, R2 = .27 Adjusted R2 = .25 Standard error = 72.11 F(2,90) = 16.47* B SE B t p sr12 -4.27 2.79 .96 1.37 -.43 .20 -4.46 2.04 .00** .04* .18 .04 -4.60 2.56 .93 1.64 -.46 .15 -4.93 1.56 .00** .12 .21 .03 * p < .05, ** p < .001; n = 93 The removal of items from the scale aimed to reduce potential bias towards people with MS. However, while the analysis of differences between the three groups on the two extraversion scores revealed that the items were likely biased towards people with MS, the regression analysis summarised in the previous table indicates that removal of these items did not change the relationship between extraversion and the other variables of the model for people with MS, but did so for controls. Therefore, the original extraversion score was used in further regression analyses for all three groups. Analyses were also conducted with and without self-esteem. The inclusion of self-esteem in the regression equation resulted in some changes. Tables 8.14 to 8.16 show the unstandardised regression co-efficients (B), the standard error (SE B), the standardised regression co-efficients (), the semipartial correlations (sr12), the probability levels (t) and significance levels (p) of the regression analysis including the original extraversion score for each group both with and without self-esteem. 24 In the first step of the analyses, with personality included, R was significantly different from zero each group (R2 = .53, adjusted R2 = .28, F(2,90) = 17.63, p < .001 for controls. R2 = .61, adjusted R2 = .37, F(2,61) = 17.68, p < .001 for people with MS. R2 = .53, adjusted R2 = .28, F(2,34) = 6.56, p < .05 for partners). Neuroticism negatively predicted the subjective quality of life of all three groups (p < .001, sr12 = .21 for controls. p < .001, sr12 = .22 for people with MS. p < .001, sr12 = .17 for partners). In addition, extraversion positively predicted the subjective quality of life of controls (p < .05, sr12 = .01). The addition of positive cognitive biases and perceived social support in the second step resulted in a significant increase in R for all three groups. Thus, hypothesis one was supported. However, there were differences between the two equations including and excluding self-esteem. For controls, with self-esteem included, perceived social support from people (p < .05, sr12 = .04) and selfesteem (p < .05, sr12 = .04) positively predicted the subjective quality of life of controls and neuroticism no longer had an effect. For people with MS, neuroticism still negatively predicted subjective quality of life (p < .05, sr12 = .01). Also, primary control negatively predicted (p < .05, sr12 = .03) and social support from people positively predicted (p < .05, sr12 = .06) subjective quality of life. For partners, at this step primary control was the only significant predictor (p < .05, sr12 = .06). With self-esteem excluded, there were additional predictors and also changes in the regression weights of some variables. For controls, without self-esteem neuroticism was a significant negative predictor (p < .001, sr12 = .08), and optimism was a significant positive predictor (p < .05, sr12 = .04). The regression weight for social support from people also increased. For people with MS, with the exclusion of self-esteem there were no additional predictors. However, the regression weights increased for extraversion, neuroticism, optimism and primary control. For partners with self-esteem excluded, there was one additional predictor. Perceived social support from people positively predicted subjective 25 quality of life (p < .05, sr12 = .09). Also, the regression weight for neuroticism increased. The addition of secondary control variables at step three did not result in a significant increase in R for any of the three groups. Therefore this step was removed from the analysis. This resulted in a higher case to variable ratio, which improved the strength of the analysis for the partners group, such that the minimum recommended five to one ratio was only exceeded in the last step of the regression. The mediating role of secondary control will be further analysed. The addition of illness variables at step four, resulted in a significant increase in R for people with MS and partners. The extent to which MS was perceived to effect their ability to live the life they would like to significantly negatively predicted subjective quality of life with or without self-esteem included (p < .05, sr12 = .08, and sr12 = .09 respectively) for people with MS. However, it was a significant predictor for partners only in the analysis with self-esteem (p < .05, sr12 = .06). The changes between the two regression equations exploring the inclusion of selfesteem suggested the presence of suppressor variable. A suppressor variable is one that is useful in predicting the dependent variable (subjective quality of life) and in increasing the multiple R2 solely by virtue of its correlations with other independent variables (Tabachnick & Fidell, 1996). However, a series of regressions, where each of the independent variables was omitted were omitted in turn to reveal the suppressor as recommended by Tabachnick and Fidell (1996) found no evidence of a suppressor variable. Thus, it appeared that the inclusion of self-esteem in the equation was weakening the analysis due to its high correlation with other variables as cautioned by Tabachnick and Fidell (1996). Table 8.14. Hierarchical Regression Analysis for Variables Predicting the Subjective Quality of Life of Controls Analysis with self-esteem Step 1 Extraversion Neuroticism R = .53, R2 = .28 Adjusted R2 = .27 Standard error = 71.44 F(2,90) = 17.63** Step 2 Extraversion Neuroticism Optimism Primary Control Self-Esteem Social support from people Social support from pets R = .67, R2 = .45 Adjusted R2 = .41 Standard error = 64.23 F(5,85) = 10.00** T .20 -.43 -.29 1.42 -.02 -1.60 1.25 -.16 3.18 1.66 .20 -2.54 2.28 -.10 2.12 .85 .32 2.23 .86 .24 .39 .59 .06 2 R inc = 17, F(5,85) = 5.27** B 2.79 -4.27 SE B 1.37 .96 p sr12 2.04 -4.46 .04* .00** .01 .21 -.20 -1.28 1.92 -1.12 2.50 2.59 .67 .84 .20 .06 .27 .01* .01* .51 .01 .00 .04 .02 .01 .04 .00 Analysis without self-esteem Step 1 Extraversion Neuroticism R = .53, R2 = .28 Adjusted R2 = .27 Standard error = 71.44 F(2,90) = 17.63** Step 2 Extraversion Neuroticism Optimism Primary Control Self-Esteem Social support from people Social support from pets R = .64, R2 = .41 Adjusted R2 = .37 Standard error = 66.81 F(4,86) = 10.00** B SE B t p sr12 2.79 -4.27 1.37 .96 .20 -.43 2.04 -4.46 .04* .00** .01 .21 .24 -3.53 3.98 -2.64 1.44 1.01 1.68 2.35 .02 -.35 .25 -.10 .16 -3.51 2.38 -1.12 .87 .00** .02* .27 .00 .08 .04 .01 2.66 .87 .29 .47 .60 .07 R inc = 13, F(4,86) = 4.74* 3.06 .77 .00* .44 .06 .00 2 * p < .05, ** p < .001; n = 93 26 Table 8.15. Hierarchical Regression Analysis for Variables Predicting the Subjective Quality of Life of People with MS Analysis with self-esteem Step 1 Extraversion Neuroticism R = .61, R2 = .37 Adjusted R2 = .35 Standard error = 91.19 F(2,61) = 17.68** Step 2 Extraversion Neuroticism Optimism Primary Control Self-Esteem Social support from people Social support from pets R = .77, R2 = .59 Adjusted R2 = .41 Standard error = 83.35 F(5,56) = 11.50** Step 3 Extraversion Neuroticism Optimism Primary Control Self-Esteem Social support from people Social support from pets.34 Years since diagnosis Effect of MS on life role R = .83, R2 = .68 Adjusted R2 = .63 Standard error = 74.68 F(9,54) = 12.89** B 1.88 -6.32 SE B 1.76 1.37 t p sr12 .12 -.54 1.07 -4.62 .29 .00** .17 .22 -.89 1.64 -.06 -3.47 1.57 -.29 2.87 2.32 .16 -7.26 3.42 -.19 1.40 1.03 .23 3.88 1.40 .28 1.23 .94 .12 2 R inc = 22, F(5,56) = 6.08** -.54 -2.20 1.24 -2.13 1.37 2.78 1.31 .59 .03* .22 .04* .18 .01* .20 .00 .01 .01 .03 .01 .06 .01 -.89 1.64 -.06 -3.47 1.57 -.29 .2.47 2.15 .14 -2.50 3.29 -.07 .85 .93 .14 3.21 1.27 .23 .34 .87 .03 -.21 1.33 -.01 -16.24 4.40 -.38 R2inc = 09, F(2,54) = 7.89** -.54 -2.20 1.5 -.76 .91 2.53 .40 -.16 -3.69 .59 .03* .26 .45 .37 .01* .70 .87 .00** .00 .03 .01 .00 .00 .04 .00 .00 .08 Analysis without self-esteem Step 1 Extraversion Neuroticism R = .61, R2 = .37 Adjusted R2 = .35 Standard error = 91.19 F(2,61) = 17.68** Step 2 Extraversion Neuroticism Optimism Primary Control Self-Esteem Social support from people Social support from pets R = .76, R2 = .58 Adjusted R2 = .53 Standard error = 83.99 F(4,57) = 12.90** Step 3 Extraversion Neuroticism Optimism Primary Control Self-Esteem Social support from people Social support from pets Years since diagnosis Effect of MS on life role R = .82, R2 = .68 Adjusted R2 = .63 Standard error = 74.55 F(2,55) = 14.45** B SE B t p sr12 1.88 -6.32 1.76 1.37 .12 -.54 1.07 -4.62 .29 .00** .17 .22 1.22 -3.86 3.74 -8.05 1.76 1.33 2.25 3.39 .08 -.33 .21 -.22 .69 -2.89 1.66 -2.37 .49 .00* .10 .02* .00 .06 .02 .04 4.61 1.30 .34 1.42 .93 .13 R inc = 21, F(4,57) = 7.02** 3.55 1.52 .00** .13 .09 .02 2 -.74 -4.39 2.99 -2.80 1.63 1.19 2.07 3.27 -.05 -.37 .17 -.08 .45 -3.68 1.45 -.86 .65 .00** .15 .40 .00 .08 .01 .00 3.62 1.18 .26 .43 .86 .04 -.29 1.32 -.02 -16.71 4.37 -.39 R2inc = 10, F(2,55) = 8.67** 3.07 .50 -.22 -3.83 .00* .62 .83 .00** .06 .00 .00 .09 * p < .05, ** p < .001; n = 65 27 Table 8.16. Hierarchical Regression Analysis for Variables Predicting the Subjective Quality of Life of Partners Analysis with self-esteem Step 1 Extraversion Neuroticism R = .53, R2 = .28 Adjusted R2 = .24 Standard error = 90.24 F(2,34) = 6.56* Step 2 Extraversion Neuroticism Optimism Primary Control Self-Esteem Social support from people Social support from pets R = .76, R2 = .57 Adjusted R2 = .47 Standard error = 75.33 F(7,29) = 5.15** Step 3 Extraversion Neuroticism Optimism Primary Control Self-Esteem Social support from people Social support from pets. Years since diagnosis Effect of MS on life role R = .79, R2 = .63 Adjusted R2 = .51 Standard error = 72.54 F(9,27) = 5.10** B 3.74 -6.02 SE B 3.07 2.10 t p sr12 .19 -.44 1.22 -2.87 .23 .00* .03 .17 -.98 3.05 -.05 -1.14 2.75 -.08 1.83 3.67 .08 8.67 4.29 .28 1.67 1.70 .21 3.27 1.64 .33 1.10 1.22 .13 2 R inc = .29, F(5,29) = 3.96* -.32 -.41 .50 2.02 .98 2.00 .90 .75 .68 .62 .05* .34 .06 .37 .00 .00 .00 .06 .01 .06 .01 -2.08 3.17 -.10 .46 2.82 .03 2.72 3.58 .13 6.71 4.24 .21 2.19 1.69 .28 2.93 1.59 .29 .90 1.18 .11 .49 1.86 .03 -12.36 5.98 -.29 R2inc = 06, F(2,27) = 2.14** -.65 .17 .76 1.58 1.30 1.84 .76 .26 -2.07 .52 .87 .45 .13 .21 .08 .46 .80 .05* .01 .00 .01 .03 .02 .05 .01 .00 .06 Analysis without self-esteem Step 1 Extraversion Neuroticism R = .53, R2 = .28 Adjusted R2 = .24 Standard error = 90.24 F(2,34) = 6.56** Step 2 Extraversion Neuroticism Optimism Primary Control Self-Esteem Social support from people Social support from pets R = .75, R2 = .56 Adjusted R2 = .47 Standard error = 75.28 F(6,30) = 6.28** Step 3 Extraversion Neuroticism Optimism Primary Control Self-Esteem Social support from people Social support from pets Years since diagnosis Effect of MS on life role R = .78, R2 = .61 Adjusted R2 = .49 Standard error = 73.42 F(2,28) = 5.40** B SE B t p sr12 3.74 -6.02 3.07 2.10 .19 -.44 1.22 -2.87 .23 .00* .03 .17 -.63 -2.98 2.02 8.58 3.03 2.01 3.67 4.29 -.03 -.22 .09 .27 -.21 -1.48 .55 2.00 .84 .15 .59 .05* .00 .03 .00 .06 3.82 1.54 .38 1.09 1.22 .13 R inc = 28, F(4,30) = 4.71* 2.48 .90 .02* .38 .09 .01 2 -1.29 -2.10 2.80 6.81 3.15 2.04 3.62 4.29 -.06 -.15 .13 .22 -.41 -1.03 .77 1.59 .69 .31 .45 .12 .06 .01 .01 .04 3.67 1.51 .37 .93 1.19 .11 .86 1.86 .06 -11.19 5.98 -.26 R2inc = .05, F(2,28) = 1.77 2.43 .78 .46 -1.87 .02* .44 .65 .07 .08 .01 .00 .05 * p < .05, ** p < .001; n = 37 28 29 In summary of the Hierarchical regression analyses, as hypothesised the variables of the model predicted a significant portion of the subjective quality of life of each group (R2 = .45 for controls, R2 = .68 for people with MS, R2 = .63 for partners). As predicted personality, specifically neuroticism, was a consistent predictor of subjective quality of life. Extraversion positively predicted the subjective quality of life of controls only. After personality was controlled for, perceived social support from people consistently predicted subjective quality of life across the three groups as hypothesised. The influence of positive cognitive bias was less consistent between the three groups and was effected by self-esteem. As discussed, self-esteem was highly correlated with the subjective quality of life of the three groups. Regression analyses were run both with and without self-esteem. While self-esteem was not acting as a suppressor variable, it nevertheless suppressed some of the variance in other variables of the model. With self-esteem removed from the regression analysis, perceived social support positively predicted the subjective quality of life of the three groups. In addition, primary control negatively predicted for people with MS, and positively predicted the subjective quality of life of partners. Optimism was a positive predictor for controls. The analysis also revealed that the effect of MS on life role predicted the subjective quality of life of people with MS when the other psychological variables of the model were controlled. Influence of Life Domains on Subjective Quality of Life Regression analyses were undertaken in order to determine the relative contribution of each domain to subjective quality for each group. Subjective quality of life could not be used as the dependent variable in this analysis as the life domains are components of the ComQol scale that measures subjective quality of life. Self-esteem was selected as a substitute dependent variables as it correlates highly with subjective quality of life (R2 = .60, p < .001 for controls, R2 = .68, p < .001 for people with MS, R2 = .56, p < .001 for partners). Correlation matrices were then generated for each group for the domains of ComQol and self-esteem to test for the presence of multicollinearity and singularity. Pearson’s correlation coefficient was calculated for people with MS and controls. Spearman Rho’s co- 30 efficient was calculated for partners. The correlation matrices are shown in Table 8.17 to 8.19. Most of the life domains were significantly correlated with other domains and with self-esteem. There was some evidence of multicollinearity that weakens regression analyses (Tabacknick & Fidell, 1996). ‘Happiness’ was removed from the regression analyses due to the high correlation with self-esteem and other domains. With seven independent variables, the ratio of cases to independent variables in the analysis was low, especially for partners. However, the ratio was greater than the minimum five to one ratio recommended by Coakes & Steed (1999). Thus, the data were suitable for regression analyses. Table 8.17. Pearson Correlations between Satisfaction with ComQol Domains and Self-Esteem for Controls Variables Possessions Health Achieve Intimacy Safety Community Happiness Independence Self Esteem Possessions Health Achieve Intimacy Safety Community Happiness Independence Self-Esteem 1.00 .40** .38** .18 .12 .24* .39** .38* .35** 1.00 .31** .26* .37** .30* .50** .45** .31** 1.00 .45** .35** .28* .65* .45* .45* 1.00 .50** .46** .58** .33* .37** 1.00 .69** .50** .32** .46** 1.00 .42** .48** .41** 1.00 .53* .52* 1.00 .03 1.00 * p < .05, ** p < .001, n = 93. Table 8.18. Pearson Correlations between Satisfaction with ComQol Domains and Self-Esteem for People with MS Variables Possessions Health Achieve Intimacy Safety Community Happiness Independence Self-esteem Possessions Health Achieve Intimacy Safety Community Happiness Independence Self-esteem 1.00 .53** .41** .58** .45** .27* .50** .20 .44** 1.00 .58** .33** .36** .27* .34** .33** .42** 1.00 .34* .34* .23 .52* .28* .60** 1.00 .58** .49** .68* .29* .58** 1.00 .69** .47* .46** .46** 1.00 .33* .18 .30* 1.00 .45* .63* 1.00 .30* 1.00 * p < .05, ** p < .001, n = 64. 31 Table 8.19. Spearman Correlations between Satisfaction with ComQol Domains and Self-Esteem for Partners Variables Possessions Health Achieve Intimacy Safety Community Happiness Independence Self-esteem Possessions Health Achieve Intimacy Safety Community Happiness Independence Self-esteem 1.00 .35* .60** .32 .46** .46** .37* .45** .32 1.00 .42** .50** .39* .09 .52** .51** .62** 1.00 .50** .30 .47** .53** .49** .35* 1.00 .62** .20 .80** .64** .58** 1.00 .46** .58** .58** .38* 1.00 .24 .18 .19 1.00 .80** .52** 1.00 .40* 1.00 * p < .05, ** p < .001, n = 37. 32 33 For controls, there was a significant R2 of .35 and an adjusted R2 of .30, F(7,85) = 6.61, p < .001. This indicates that the regression model accounted for 35% of the variance in self-esteem. There was one significant predictor, satisfaction with achievements positively influenced the self-esteem of controls (p < .05, sr12 = .03). Table 8.20 shows the unstandardised regression co-efficients (B), the standard error (SE B), the standardised regression co-efficients (), the semi-partial correlations (sr12), the probability levels (t) and significance levels (p) for each variable. Table 8.20 Regression Analysis of the Effect of the Domains of ComQol on the Self-Esteem of Controls Variables in equation Possessions Health Achieve Intimacy Safety Community Independence R = .59, R2 = .35 Adjusted R2 = .30 Standard error = 10.64 F(7,85) = 6.61** B 1.39 .27 1.76 .55 2.24 .76 -.21 SE B .78 .77 .84 .97 1.20 .93 .88 .19 .04 .23 .06 .25 .11 -.03 t 1.80 .35 2.10 .57 1.86 .82 -.24 p .08 .72 .04* .57 .07 .41 .81 sr12 .03 .00 .03 .00 .03 .01 .00 * p < .05, ** p < .001; n = 93 For people with MS, There was a significant R2 of .53 and an adjusted R2 of .47, F(7,56) = 8.93, p < .001. This indicates that the regression model accounted for 53% of the variance in self-esteem. There were two significant predictors. This regression indicates that satisfaction with achievements (p < .001, sr12 = .12) with close relationships (p < .05, sr12 = .07) positively influenced the self-esteem of people with MS. This analysis is summarised in Table 8.21. 34 Table 8.21 Regression Analysis of the Effect of the Domains of the ComQol on the SelfEsteem of People with MS Variables in equation Possessions Health Achieve Intimacy Safety Community Independence R = .73, R2 = .53 Adjusted R2 = .47 Standard error = 14.88 F(7,56) = 8.93** B -.01 .11 3.80 3.18 .75 -.27 .30 SE B 1.08 1.15 1.02 1.09 1.21 1.00 .90 -.00 .01 .43 .39 .08 -.03 .04 t -.01 .09 3.72 2.93 .62 -.27 .34 p .99 .93 .00** .01* .54 .79 .74 sr12 .00 .00 .12 .07 .00 .00 .00 * p < .05, ** p < .001; n = 64 For partners, there was a significant R2 of .47 and an adjusted R2 of .34, F(7,29) = 3.63, p < .05. This indicates that the regression model accounted for 47% of the variance in self-esteem. There were two significant predictors. Satisfaction with one’s health (p < .05, sr12 = .09) and close relationships (p < .05, sr12 = .10) positively influenced the self-esteem of partners. This analysis is summarised in Table 8.22. Table 8.22 Regression Analysis of the Effect of the Domains of the ComQOL on the SelfEsteem of Partners Variables in equation Possessions Health Achieve Intimacy Safety Community Independence R = .68, R2 = .47 Adjusted R2 = .34 Standard error = 10.61 F(7,29) = 3.63* * p < .05, ** p < .001; n = 37 B .12 2.59 -.71 3.65 -1.03 1.48 -.40 SE B 1.24 1.14 1.55 1.60 1.75 1.52 1.42 .02 .39 -.11 .55 -.13 .18 -.06 t .10 2.26 -.46 2.28 -.59 .97 -.28 p .92 .03* .65 .03* .56 .34 .78 sr12 .00 .09 .01 .10 .01 .02 .00 35 In summary, in regards, to the influence of the life domains on self-esteem, which is highly related to subjective quality of life, satisfaction with happiness was highly correlated for each of the groups. In addition, satisfaction with achievements positively predicted the self-esteem of controls and people with MS. Satisfaction with close relationships predicted the self-esteem of people with MS and partners. Satisfaction with health predicted the self-esteem of partners. Life Circumstances and Stressors The stress caused by MS was assessed by asking ‘how severely does your/ or your partner’s condition effect your ability to perform the role you would like to in life?’ It was hypothesised that personality and perceived social support effect perceptions of MS as a stressor. Specifically, that high neuroticism, low extraversion, and low perceived social support correlate positively with the perceived extent to which MS effects life roles. In order to assess the influence of neuroticism, extraversion, and perceived social support on this assessment of stress, these variables were entered into a multiple regression with effect on life role as the independent variable for both people with MS and partners. For people with MS, there was a significant R2 of .20 and an adjusted R2 of .15, F(4,59) = 3.72, p < .05. This indicates that the regression model accounted for 20% of the variance in the extent to which people perceived that MS effected their life role. There were two significant predictors. Extraversion (p < .05, , sr12 = .09) and perceived social support from pets (p < .05, , sr12 = .07) negatively predicted the extent to which MS was perceived as effecting life roles. Table 8.23 shows the unstandardised regression co-efficients (B), the standard error (SE B), the standardised regression co-efficients (), the semi-partial correlations (sr12), the probability levels (t) and significance levels (p) for each variable. 36 Table 8.23. Regression Analysis of the Effect of Personality and Perceived Social Support on Assessment of Life Role for People with MS Variables in equation Neuroticism Extraversion Perceived Social Support from people Perceived Social Support from Pets R = .45 R2 = .20 Adjusted R2 = .15 F (4,59) = 3.72* B -.03 -.14 -.07 -.07 SE B .04 .06 .04 .03 t p -.10 -.32 -.23 -.27 -.69 -2.37 -1.87 -2.24 .49 .02* .07 .03* Sr12 .01 .09 .05 .07 * p < .05, n = 64. The regression model was not significant for partners, indicating that neither personality nor social support influenced the extent to which they perceived that their partner’s MS influenced their ability to live the life they would like to. The Mediating Role of Secondary Control Hypothesis 3 predicted that secondary control mediates between positive cognitive bias and subjective quality of life. The mediating role of secondary control was tested through a series of regressions as recommended by Baron and Kenny (1986). In order to test for mediation, three regression equations are recommended. Firstly, the mediator (secondary control) is regressed on the independent variable (positive cognitive bias). The dependent variable (subjective quality of life) is then regressed on the independent variable (positive cognitive bias). Finally, the dependent variable (subjective quality of life) is regressed both on the independent variable (positive cognitive bias) and the mediator (secondary control). Mediation is evidenced by an effect of the independent variable in both the first equation and second equation, and an effect of the mediator on the dependent variable in the third equation. If these conditions all hold, then the effect of the independent variable on the dependent variable must be less in the third equation than in the second. The analysis based on this hypothesis is represented by the bold lines in Figure 8.5. 37 FIRST ORDER DETERMINANTS: Personality SECOND ORDER DETERMINANTS: Internal Buffers THIRD ORDER MEDIATING DETERMINANT Perceived Social Support Extraversion Neuroticism Positive Cognitive Biases Self-Esteem Optimism Primary Control Subjective Quality of Life Secondary Control Environmental Factors Figure 8.5 Analysis of Hypothesis 3: The Mediating Role of Secondary Control In order to undertake these analyses, the three positive cognitive biases: selfesteem, primary control and optimism were summed to form one total positive cognitive bias score. In order for a total secondary control score to be generated for each group, regression analyses were undertaken to determine which of the five types of secondary control influenced subjective quality of life. Tables 8.24 to 8.26 shows the unstandardised regression co-efficients (B), the standard error (SE B), the standardised regression co-efficients (), the semi-partial correlations (sr12), the probability levels (t) and significance levels (p) for each group. For controls, there was a significant R2 of .13 and an adjusted R2 of .08, F(5,87) = 2.49, p < .05. This indicates that the regression model accounted for 8% of the variance in subjective quality of life. There was one significant predictor. Ventilation (p < .05, , sr12 = .07) negatively predicted subjective quality of life. 38 Table 8.24. Regression Analysis of the Effect of the Five Types of Secondary Control on the Subjective Quality of Life of Controls Variables in equation Ventilation Self-Protective Secondary Control Situation Bias Secondary Control Avoidant Secondary Control Self-Affirmative Secondary Control R = .35 R2 = .13 Adjusted R2 = .08 F (5,87) = 2.49* B -22.72 -2.83 -.17 -6.62 3.83 t p -.28 -.09 -.00 -.16 -.18 -2.61 -.73 -.03 -1.38 1.39 .01* .47 .97 .17 .17 SE B 8.70 3.86 5.12 4.79 2.75 sr12 .07 .01 .00 .02 .02 * p < .05, ** p < .001; n = 93. For people with MS, there was a significant R2 of .31 and an adjusted R2 of .25, F(5,58) = 5.16, p < .05. This indicates that the regression model accounted for 25% of the variance in subjective quality of life. There were two significant predictors. Ventilation (p < .001, sr12 = .23) and avoidant secondary control (p < .05, sr12 = .12) negatively predicted subjective quality of life. Table 8.25. Regression Analysis of the Effect of the Five Types of Secondary Control on the Subjective Quality of Life of People with MS Variables in the equation Ventilation Self-Protective Secondary Control Situation Bias Secondary Control Avoidant Secondary Control Self-Affirmative Secondary Control R = .56 R2 = .31 Adjusted R2 = .25 F (5,58) = 5.16* B SE B t p -56.70 .24 -6.13 -19.76 .92 12.85 4.29 9.00 6.13 4.97 -.50 .01 -.09 -.39 .03 -4.41 .06 -.68 -3.23 .19 .00** .96 .50 .00** .85 sr12 .23 .00 .01 .12 .00 * p < .05, ** p < .001; n = 65. For partners, there was a significant R2 of .43 and an adjusted R2 of .33, F(5,31) = 4.62, p < .05. This indicates that the regression model accounted for 33% of the 39 variance in subjective quality of life. There were two significant predictors. Ventilation (p < .05, sr12 = .14) negatively predicted and situation bias secondary control (p < .001, sr12 = .31) positively predicted subjective quality of life. Table 8.26. Regression Analysis of the Effect of the Five Types of Secondary Control on the Subjective Quality of Life of Partners Variables in the equation Ventilation Self-Protective Secondary Control Situation Bias Secondary Control Avoidant Secondary Control Self-Affirmative Secondary Control R = .65 R2 = .43 Adjusted R2 = .33 F (5,31) = 4.62* B SE B t p -44.92 -2.39 37.22 -13.00 .27 16.50 5.32 9.09 6.69 3.78 -.40 -.07 .66 -.30 .01 -2.72 -.45 4.09 -1.94 .07 .01* .66 .00** .06 .94 sr12 .14 .00 .31 .07 .00 * p < .05, ** p < .001; n = 65. In summary, while ventilation negatively predicted the subjective quality of life of the three groups, avoidant secondary control negatively predicted the subjective quality of life of people with MS, and situation bias secondary control positively predicted the subjective quality of life of partners. A total secondary control score was generated for each of the groups based on these regressions. For people with MS this score comprised of the sum of the ventilation and avoidant secondary control scores. For partners this comprised the sum of the ventilation score and the inverse of the situation bias secondary control score. For controls this comprised the ventilation score only. The series of three regressions recommended by Baron and Kenny (1986) were then undertaken for each of the three comparison groups to test for the mediating role of secondary control. For controls, the analyses revealed that secondary control mediated between positive cognitive biases and subjective quality of life. This was evidenced by the 40 three significant regression equations, and the reduced impact of positive cognitive bias in the third equation (sr12 = .29) compared to the second (sr12 = .36). These regression analyses are summarised in Table 8.27. Table 8.27 Regression Analysis of the Mediating Effect of Secondary Control for Controls Regressions 1. Regression of total secondary control on total positive cognitive bias R = .35 R2 = .12 Adjusted R2 = .11 F (1,91) = 12.80** 2. Regression of subjective quality of life on total positive cognitive bias R = .60 R2 = .36 Adjusted R2 = .36 F (1,91) = 51.99** 3. Regression of subjective quality of life on: total positive cognitive bias total secondary control R = .61 R2 = .37 Adjusted R2 = .36 F (2,90) = 26.48** * p < .05, ** p < .001, n = 93 B -.02 SE B .01 t p -.35 -3.58 .00** .12 sr12 2.93 .41 .60 7.21 .00** .36 2.78 -7.10 .43 7.17 .57 -.09 6.40 -.99 .00** .33 .29 .01 41 For people with MS, the analyses revealed that secondary control mediated between positive cognitive biases and subjective quality of life. This was evidenced by the three significant regression equations, and the reduced impact of positive cognitive bias in the third equation (sr12 = .27) compared to the second (sr12 =.43). These regression analyses are summarised in Table 8.28. Table 8.28 Regression Analysis of the Mediating Effect of Secondary Control for People with MS Regressions 1. Regression of total secondary control on total positive cognitive bias R = .46 R2 = .21 Adjusted R2 = .20 F (1,62) = 16.56** 2. Regression of subjective quality of life on total positive cognitive bias R = .66 R2 = .43 Adjusted R2 = .42 F (1,62) = 46.80** 3. Regression of subjective quality of life on: total positive cognitive bias total secondary control R = .68 R2 = .46 Adjusted R2 = .44 F (2,61) = 25.81** * p < .05, ** p < .001, n = 65 B SE B t p -.04 .01 -.46 -4.07 .00** .21 3.11 .46 .66 6.84 .00** .43 2.70 -9.75 .50 5.47 .57 -.19 5.37 -1.78 .00** .08 .27 .03 sr12 42 For partners, the analyses revealed that secondary control mediated between positive cognitive biases and subjective quality of life for the control group. This was evidenced by the three significant regression equations, and the reduced impact of positive cognitive bias (sr12 = .18) in the third equation compared to the second (sr12 = .44). The regressions are summarised in Table 8.29. Table 8.29 Regression Analysis of the Mediating Effect of Secondary Control for Partners Regressions 1. Regression of total secondary control on total positive cognitive bias R = .56 R2 = .32 Adjusted R2 = .30 F (1,35) = 15.31** 2. Regression of subjective quality of life on total positive cognitive bias R = .66 R2 = .44 Adjusted R2 = .42 F (1,35) = 27.50** 3. Regression of subjective quality of life on: total positive cognitive bias total secondary control R = .72 R2 = .51 Adjusted R2 = .48 F (2,34) = 16.75** t .02 .56 -3.91 .00* .32 3.94 .75 .66 5.24 .00** .44 3.09 -16.42 .90 8.64 .52 -.28 3.45 -1.90 .00* .07 .18 .06 B .05 SE B p sr12 * p < .05, ** p < .001, n = 37 In summary, consistent with hypothesis three, secondary control was found to mediate between positive cognitive biases and subjective quality of life for each of the three groups but to unequal extents. The reduction in the influence of positive cognitive bias on subjective quality of life from the second regression equation to the third was the most for people with MS (.26), then partners (.16), and least for controls (.07). 43 The Role of Perceived Social Support It was hypothesised that effect of perceived social support on subjective quality of life is subject to a threshold effect such that it is more strongly associated with the subjective quality of life for people under stress. The hypothesis stated: Hypothesis 6: Perceived social support is more strongly correlated with subjective quality of life for people with MS than partners and controls. The analysis based on this hypothesis is represented by the bold lines in Figure 8.6. FIRST ORDER DETERMINANTS: Personality SECOND ORDER DETERMINANTS: Internal Buffers THIRD ORDER MEDIATING DETERMINANT Perceived Social Support Extraversion Neuroticism Positive Cognitive Biases Self-Esteem Optimism Primary Control Subjective Quality of Life Secondary Control Environmental Factors Figure 8.6 Analysis of Hypothesis 6: The Threshold Effect of Perceived Social Support 44 In order to address this hypothesis, participants were categorised as perceiving either high or low levels of social support. By doing so, interaction effects between group membership and levels of perceived social support could be explored through an ANOVA. The means (X) and standard deviations (SD) of subjective quality of life at the two levels of perceived social support are shown in Table 8.30. Table 8.30. Subjective Quality of Life by Group Membership and Level of Perceived Social Support. People with MS Perceived Social Support High Perceived Social Support X SD Low Perceived Social Support X SD Controls N = 36 57.31 15.27 Partners of People with MS N= 21 68.78 13.84 N= 28 73.65 13.07 N= 16 81.25 11.39 N= 41 78.79 10.00 N = 52 72.93 12.22 In order to determine whether the effect of perceived social support on subjective quality of life varied according to group membership, a two-way ANOVA of subjective quality of life by group membership (i.e. person with MS, partner of a person with MS, control) and perceived social support (i.e. high and low) was undertaken seeking interaction effects. Levene’s Test was not significant at p > .05, indicating that the data were suitable for the analysis. This analysis is shown in Table 8.31. 45 Table 8.31 Analysis of Variance Examining the Interaction between Subjective Quality of Life, Group Membership and Perceived Social Support Source Perceived Social Support Group Membership Perceived Social Support*Group Membership F 36.22** 16.52** 3.88* Power 1.00 1.00 1.00 ² .16 .15 .04 * p < .05. ** p < .001, ² = strength of association, n = 194 The analysis demonstrated a significant main effect for group membership, perceived social support, and an interaction effect F(2,193) = 3.88, p < .05. The interaction effect is shown in Figure 8.7 The 700 600 Subjective Quality of Life 500 PERSON WITH MS PARTNER OF PWMS 400 Low CONTROL High Perceived Social Support Figure 8.7 The Interaction between Perceived Social Support, Group Membership and Subjective Quality of Life ANOVAs with subjective quality of life as the dependent variable were carried out to explore the simple effects of the interaction between group membership, 46 level of perceived social support, and subjective quality of life. ANOVAs were conducted to determine whether there was a main effect for level of social support for each group. These are summarised in Table 8.32. Consistent with previous analysis, high levels of perceived social support were associated with significantly higher subjective quality of life than low levels of perceived social support for each group. Table 8.32 Univariate Analyses of Variance Examining the Difference in Subjective Quality of Life between the Two Levels of Perceived Social Support Source People with MS Partners of People with MS Controls F 21.76** 8.83** 6.16* power .99 .82 .69 ² .26 .20 .06 * p < .05, ** p < .001, ² = strength of association. ANOVAs were also undertaken at each level of perceived social support (high and low) to determine whether there was a main effect for group. These analyses revealed a main effect of group at both low and high levels of perceived social support. These two analyses are summarised in Table 8.33. Table 8.33 Simple Effects of Group Membership at the Two Levels of Perceived Social Support Source Low Perceived Social Support High Perceived Social Support F 14.47** 3.67* power .99 .66 ² .26 .07 * p < .05, ** p < .001, n = 194, ² = strength of association Univariate tests revealed that in the low perceived social support condition the subjective quality of life of people with MS was significantly lower than both partners (p < .05) and controls (p < .001). In the high perceived social support 47 condition the subjective quality of life of people with MS was significantly lower than partners (p < .05). In summary, these findings support Hypothesis 6. Perceived social support effected subjective quality of life differently between the three groups. People with MS reported a lower subjective quality of life than the other two groups at levels of low perceived social support. At levels of high perceived social support their subjective quality of life differed only from partners. It was hypothesised that perceived social support from pets is similarly more strongly associated with subjective quality of life for people with MS than partners and controls. An ANOVA revealed no significant difference in the amount of perceived social support from pets between the three groups. Analyses similar to that undertaken to explore the relative influence of perceived social support from people, and primary and secondary control were not possible as substantially fewer people responded to the questionnaire items pertaining to pets. Specifically, 58 (of 93) controls, 26 (of 37) partners, and 48 (of 64) people with MS responded to the items pertaining to pets. Splitting of perceived social support from pets into levels (e.g. high and low) was not viable as it yielded too few cases in each cell of the analysis. Thus, in order to determine the unique effect of this support on subjective quality of life, a correlation matrix was generated. The means (X), standard deviations (SD), and correlation co-efficients of perceived social support from pets and subjective quality of life are shown in Table 8.34. 48 Table 8.34. Correlations between Perceived Social Support from Pets with Subjective Quality of Life Total Perceived Social Support from Pets X 68.72 SD 28.13 Correlation with Subjective Quality of Life .25* Partners of People with MS X 80.26 SD 18.93 .44** Controls X 68.39 SD 25.73 .05 Group People with MS * p < .05, ** p < .001. While the control group reported no association between perceived social support from pets and their subjective quality of life, people with MS reported a significant positive association. In contrast with the hypothesis, partners reported an even stronger positive association between perceived social support from pets and their subjective quality of life. The Adaptive Function of Primary and Secondary Control Integral to the adaptive functioning of the model is the adaptive functioning of primary and secondary control. It was hypothesised that: Hypothesis 7: The use of secondary control is positively associated with the subjective quality of life of people with MS and partners, but not controls. The use of primary control is negatively associated with the subjective quality of life of people with MS and partners, but not controls. Hypothesis 8: Individuals with high levels of both primary and secondary control have a higher subjective quality of life than those who exhibit a preference for either primary or secondary control. 49 The analysis based on this hypothesis is represented by the bold lines in Figure 8.8. FIRST ORDER DETERMINANTS: Personality SECOND ORDER DETERMINANTS: Internal Buffers THIRD ORDER MEDIATING DETERMINANT Perceived Social Support Extraversion Neuroticism Positive Cognitive Biases Self-Esteem Optimism Primary Control Secondary Control Subjective Quality of Life Environmental Factors Figure 8.8 Analysis of Hypothesis 7 and 8: The Adaptive Outcome of Primary and Secondary Control In order to explore the adaptive outcome of a balance between primary and secondary control for the three groups a strategy similar to that utilised to explore the effect of perceived social support and group membership on subjective quality of life was undertaken. Similarly, the sample was split into groups based on primary and secondary control levels. The sample was initially split into four groups representing the four possible combinations of primary and secondary control: high primary, high secondary; high primary, low secondary; low primary, high secondary; low primary, low secondary. Unfortunately, this split yielded groups with as few as four participants in some cells. Therefore, three groups were retained for the analysis: high primary, high secondary; low primary, low 50 secondary; and a group called ‘unbalanced control’, which was a combination of the two groups high primary, low secondary and low primary, high secondary. The means and standard deviations of subjective quality of life for these three groups are shown in Table 8.35. Table 8.35. Subjective Quality of Life by Group Membership and Relative Levels of Primary and Secondary Control. Levels of Control People with MS High Primary, High Secondary X SD N = 25 62.86 13.14 Partners of People with MS N=8 85.63 7.10 Controls Low Primary, Low Secondary X SD N = 15 74.58 16.90 N = 16 71.72 15.77 N = 37 76.99 10.61 Unbalanced Control X SD N = 24 64.69 17.49 N = 13 74.94 12.07 N = 37 74.73 12.05 N = 28 76.65 11.86 In order to determine whether the levels of primary and secondary control exerted a different effect on subjective quality of life between the three groups, a two-way ANOVA was conducted seeking interactions with subjective quality of life as the dependent variable, and group membership (person with MS, partner, or control), and levels of primary and secondary control as the factors. Levene’s was not significant at p> .001 indicating that the data were suitable for this analysis. The analysis is summarised in Table 8.36. 51 Table 8.36 Analysis of Variance Examining the Interaction between Subjective Quality of Life and Levels of Control Source Levels of Control Group Membership Levels of Control*Group Membership F 1.30 10.87** 3.29* ² .01 .11 .07 power .28 .99 .83 * p < .05. ** p < .001, n = 194, ² = strength of association The analysis revealed a significant main effect for group membership, F(2,193) = 10.87, p < .001 and an interaction effect between levels of primary and secondary control and group membership F(4,193) = 3.29, p < .05. The interaction is shown in Figure 8.9. 700 600 Subjective Quality of Life 500 PERSON WITH MS PARTNER OF PWMS 400 low primary low secondary CONTROL unbalanced hi primary hi secondary Figure 8.9 Interaction Between Relative Levels of Primary and Secondary Control and Group Membership on Subjective Quality of Life. 52 ANOVAs with subjective quality of life as the dependent variable were carried out to explore the simple effects of the interaction between group membership and level of primary and secondary control. ANOVAs were conducted within each group to determine whether the three levels of primary and secondary control exerted an effect on subjective quality of life. There was no effect for each of the three groups. Thus, subjective quality of life did not differ within the three groups based on the relative use of primary and secondary control. ANOVAs were also undertaken to determine whether there were differences between the three groups on subjective quality of life at each level of control. These analyses revealed a main effect of group at conditions of both high primary/high secondary and unbalanced control for the three groups. Univariate tests demonstrated that in the high primary/high secondary condition the subjective quality of life of people with MS was significantly lower than both partners and controls (p < .001). In the unbalanced control condition the subjective quality of life of people with MS was also significantly lower than controls (p < .05). The three analyses are summarised in Table 8.37. Table 8.37 Simple effects of Group membership and Levels of Primary and Secondary Control Source High Primary High Secondary Unbalance Low Primary Low Secondary F 15.99** 3.95* .79 Power .99 .69 .18 ² .36 .11 .02 * p < .05, ** p < .001, n = 194, ² = strength of association In summary, while the relative use of primary and secondary control did not differ between controls and partners, people with MS reported a significantly lower subjective quality of life than partners and controls in the unbalanced control and high primary/high secondary control condition. 53 In order to determine whether primary and secondary control individually interacted with group membership to influence subjective quality of life, the above analysis was repeated examining separately levels of primary and secondary control separately. The means (X) and standard deviations (SD) of subjective quality of life for the three groups at the various levels of primary and secondary control are shown in Table 8.38. 54 Table 8.38. Subjective Quality of Life by Group Membership and Levels of Primary and Secondary Control. Levels of Control People with MS Partners of People with MS N = 13 84.65 7.86 Controls High Primary X SD N = 34 63.10 16.31 N = 40 76.34 12.18 Low Primary X SD N = 30 69.92 15.69 N = 24 71.09 14.12 N = 53 76.11 10.80 High Total Secondary X SD N = 40 63.77 13.09 N = 16 77.73 12.08 N = 49 75.72 11.60 Low Total Secondary X SD N =24 70.52 20.00 N = 21 74.43 15.15 N = 44 76.65 11.23 High Ventilation X SD N= 38 63.18 17.22 N = 21 72.26 15.79 N = 48 74.25 12.44 Low Ventilation X SD N = 26 70.86 13.86 N = 16 80.58 9.17 N = 45 78.30 9.78 High Situation Bias X SD N = 38 63.98 15.53 N = 16 82.08 11.89 N = 54 76.69 11.45 Low Situation Bias X SD N = 26 69.71 16.97 N = 22 71.62 13.67 N = 39 75.55 11.34 High Self-Protective X SD N = 32 64.31 14.01 N = 16 76.75 14.24 N = 28 75.19 11.76 Low Self-Protective X SD N = 32 68.32 18.17 N = 21 75.25 13.84 N = 65 76.65 11.24 High Avoidant X SD N = 36 63.15 14.56 N = 21 72.98 13.80 N = 37 75.20 8.13 Low Avoidant X SD N = 27 70.60 17.66 N = 16 79.64 13.34 N = 56 76.88 13.09 High Self-Affirmative X SD N =28 65.80 13.78 N = 16 76.95 12.67 N = 55 76.89 11.23 Low Self-Affirmative X SD N = 35 66.79 18.18 N = 21 75.03 14.89 N = 38 75.23 11.62 55 In order to determine whether the effect of either primary or secondary control on subjective quality of life varied according to group membership, a three-way ANOVA of subjective quality of life by group membership (i.e. person with MS, partner, or control), level of primary control, total secondary control level and the levels of the five types of secondary control was undertaken seeking interaction effects. Levene’s test was not significant at p> .001 indicating that the data were suitable for this analysis. The analysis is shown in Table 8.39. Table 8.39 Analysis of Variance Examining the Interaction between Subjective Quality of Life and Levels of Primary and Secondary Control F 10.73** Power .99 ² .11 Levels of Primary Control Levels of Primary Control*Group Membership 1.92 5.51* .28 .85 .01 .06 Levels of Secondary Control Levels of Secondary Control*Group Membership 1.24 .87 .20 .20 .01 .01 12.91** 1.25 .95 .27 .07 .01 Levels of Situation bias Levels of Situation bias*Group Membership 1.19 3.77* .19 .68 .01 .04 Levels of Self-Protective Levels of Self-Protective*Group Membership .01 .06 .05 .06 .00 .01 7.85* 1.31 .80 .28 .04 .02 .46 .35 .10 .11 .01 .01 Source Group Membership Levels of Ventilation Levels of Ventilation*Group Membership Levels of Avoidant Levels of Avoidant*Group Membership Levels of Self-Affirmative Levels of Self-Affirmative*Group Membership * p < .05. ** p < .001, n = 194, ² = strength of association. Consistent with previous analyses, there was a significant effect of group membership. There was also a main effect for ventilation and avoidant secondary control, with lower subjective quality of life associated with higher levels of both. There was no significant effect for levels of secondary control, no significant 56 effect for levels of primary control and no interaction effect between secondary control and group membership. However, there were two significant interaction effects. There was an interaction effect between levels of primary control and group membership F(2,188) = 6.34, p < .05, and one between levels of situation bias secondary control and group membership F(2,188) = 3.77, p < .05 . The simple effects of both are now analysed in turn. The interaction between primary control and group membership is analysed first and is shown in Figure 8.10 700 600 Subjective Quality of Life PERSON WITH MS PARTNER OF PWMS 500 Low Primary Control CONTROL High Primary Control Figure 8.10 The Interaction between Primary Control, Group Membership and Subjective Quality of Life ANOVAs were carried out to explore the simple effects of group membership of the interaction between primary control and subjective quality of life. ANOVAs were conducted for each group to determine whether there was a difference in subjective quality of life between the two levels of primary control. The two levels of primary control were associated with a significant difference in the subjective quality of life of partners, F(3,33) = 9.80, p < .001, but not of the other 57 two groups. Partners reported a higher level of subjective quality of life at high levels of primary control compared to low levels. ANOVAs were also undertaken at each level of primary control (high and low) to determine whether there were differences in subjective quality of life between the three groups. These two analyses are summarised in Table 8.40. Table 8.40. Simple Effects of Group Membership on Subjective Quality of Life Source High Primary Low Primary F 16.88** 2.90 power 1.00 .56 ² .29 .05 * p < .05, ** p < .001, n = 194, ² = strength of association In the high primary condition there was a significant effect of group on subjective quality of life. Univariate tests revealed that in the high primary condition the subjective quality of life of people with MS was significantly lower than both partners and controls (p < .001). The interaction between group membership, situation bias secondary control, and subjective quality of life is now analsyed. This interaction is shown in Figure 8.11. 58 700 600 Subjective Quality of Life PERSON WITH MS PARTNER OF PWMS 500 Low Situation Bias CONTROL High Situation Bias Figure 8.11 The Interaction between Situation Bias Secondary Control, Group Membership and Subjective Quality of Life ANOVAs were carried out to explore the simple effects the interaction between group membership, situation bias secondary control and subjective quality of life. ANOVAs were conducted for each group to determine whether there was a difference in subjective quality of life between the two levels of situation bias secondary control. The was a significant difference in subjective quality of life between the two levels of situation bias secondary control for partners, F(3,33) = 5.82, p < .05, but not for the other two groups. Partners reported a higher level of subjective quality of life at high levels of situation bias control compared to low levels. ANOVAs were also undertaken at each level of situation bias secondary control (high and low) to determine whether there were differences in subjective quality of life between the three groups. These three analyses are summarised in Table 8.41 59 Table 8.41. Simple Effects of Group Membership, Situation Bias, and Subjective Quality of Life Source High Situation Bias Low Situation Bias F 16.09** 1.79 power 1.00 .36 ² .24 .04 * p < .05, ** p < .001, n = 194, ² = strength of association In the high situation bias condition there was a significant effect of group on subjective quality of life. Univariate tests revealed that in the high situation bias condition the subjective quality of life of people with MS was significantly lower than both partners and controls (p < .001). In summary, the adaptive outcome of primary and secondary control differed between the three groups. There were no differences in subjective quality of life within the groups based on relative levels of total primary and secondary control, . However, when the three groups were compared it was apparent that people with MS fared worse than the other two groups at balanced levels of control, and worse still at levels of high primary and secondary control. In regards to the use of secondary control, there were no differences in subjective quality of life based on absolute levels of secondary control and there was no interaction with group membership. However, when the five types of secondary control were separately analysed, some differences between the groups were evident. Ventilation negatively predicted the subjective quality of life of the three groups, avoidant secondary control negatively predicted the subjective quality of life people with MS, and situation bias secondary control positively predicted the subjective quality of life of partners. There was one interaction effect that was between situation bias secondary control and group membership. Partners reported a higher subjective quality of life at conditions of high situation bias secondary control. Also when the three groups were compared people with MS 60 fared significantly worse than the other two groups at high levels of situation bias secondary control. There was also an interaction between group membership and levels of primary control. Partners were the only group who differed in their subjective quality of life based on levels of primary control. They reported a higher subjective quality of life at high levels of primary control. When the three groups were compared, it was apparent that primary control effected subjective quality of life differently between the three groups. Specifically, people with MS reported a lower subjective quality of life compared to the other two groups, at levels of high primary control.