1
Summary of Results
The results are summarised as follows:
Preliminary Analyses
Most of the variables were normally distributed for the three groups, however some deviated mildly from normality. Transformations of the data were not undertaken. All of the scales were found to be reliable for each of the three groups. The addition of new items to the Primary and Secondary Control Scale, the ComQol and the Perceived Social Support Scale were confirmed for inclusion in the study. A factor analysis of the Primary and Secondary Control Scale confirmed the proposed factor structure of control. The new items however, did not load onto the predicted factors. The new item ‘give up’ loaded with avoidant secondary control, rather than primary control as predicted. Thus, this item was categorised as avoidant secondary control for subsequent analysis. The new item
‘ventilation’ did not load with any other scale items, however this was retained for analysis, as it was proposed that this may represent a new type of secondary control. Three items of the extraversion subscale of the NEO Five-Factor
Inventory were initially removed from analysis as they were likely biased in relation to people with MS. However, they were included in regression analyses as their inclusion did not change the way that extraversion interacted with other variables for people with MS and partners.
The Proposed Model for the Maintenance of Subjective Quality of Life
Results related to the hypotheses based on the proposed model for the maintenance of subjective quality of life are now summarised:
Hypothesis 1: The subjective quality of life of the three comparison groups differs, such that people with MS have the lowest subjective quality of life. Partners have a higher, and controls have the highest subjective quality of life.

This hypothesis was in part supported. As predicted, people with MS reported a lower subjective quality of life than both partners and controls. However, the subjective quality of life of partners did not differ from controls. There was no
2 difference between the subjective quality of life of people with different types of
MS.
Hypothesis 2: Perceived social support and positive cognitive biases will predict subjective quality of life after the variance contributed by personality has been controlled.
As predicted, the variables of the proposed model for the maintenance of subjective quality of life predicted a substantial proportion of subjective quality of life. Positive cognitive biases and perceived social support predicted subjective quality of life after the variance contributed by personality has been controlled
Self-esteem was strongly associated with the subjective quality of life and with other variables of the model, most notably neuroticism, for all three groups. As hypothesised, perceived social support from people also positively predicted subjective quality of life.
The variables of the model interacted differently between the three groups.
The subjective quality of life of controls was additionally positively predicted by optimism. Primary control positively predicted the subjective quality of life of partners and negatively predicted that of people with MS. When all variables of the model were controlled, the extent to which MS effected their life role also negatively predicted their subjective quality of life.
The analyses also revealed some unexpected differences between the three groups on the variables of the model. People with MS reported more avoidant secondary control than controls and partners reported lower perceived social support than the other two groups. In regards to the domains of the ComQol, people with MS were less satisfied with their health and how safe they felt than both partners and

controls. They were also less satisfied than controls with what they had achieved and their happiness. Although people with MS rated their independence significantly more important than controls they were significantly less satisfied
3 with their independence than controls.
The independence life domain did not significantly contribute to self-esteem, which was highly related to subjective quality of life, of each group. Satisfaction with the ‘happiness’ life domain was highly correlated with self-esteem, which is highly related to subjective quality of life for each group. 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.
Hypothesis 3: Secondary control mediates between positive cognitive biases and subjective quality of life.
This hypothesis was supported. Secondary control mediated between positive cognitive biases and subjective quality of life for all three groups. However, the extent to which secondary control mediated varied between the three groups.
Secondary control mediated to the greatest extent for people with MS, to a lesser extent for partners, and least controls.
The Magnitude of Positive Cognitive Biases
Hypothesis 4: Positive cognitive biases of primary control and selfesteem are smaller for people with MS than partners and controls.
This hypothesis was in part supported. There was no difference between the three groups regarding primary control. However, as predicted people with MS reported a lower self-esteem than both partners and controls.

Hypothesis 5: Optimism is higher for people with MS than partners and controls.
This hypothesis was not supported. Positive cognitive biases of optimism did not differ between the three groups.
4
Perception of Life Circumstances
Hypothesis 6: High neuroticism, low extraversion and low perceived social support positively predict perceptions of MS as stressful.
This hypothesis was explored in relation to people with MS and partners and was somewhat supported. Extraversion and perceived social support from pets negatively predicted the extent to which MS was perceived to effect life roles for people with MS but not for partners.
The Threshold Effect of Perceived Social Support
Hypothesis 7: Perceived social support is more strongly associated with subjective quality of life for people with MS, than partners and controls.
In support of hypothesis seven, perceived social support was subject to a threshold effect, such that people with MS reported a lower subjective quality of life at low levels of perceived social support than the other two groups. Whilst not a significant predictor of subjective quality of life, as expected the effect of perceived social support from pets on subjective quality of life was stronger for people with MS and partners than for controls.
The Adaptive Outcome of Primary and Secondary Control
Results related to the hypotheses based on the adaptive outcome of primary and secondary control are now summarised:

Hypothesis 8: 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.
This hypothesis was in part supported. In contrast to the hypothesis, there were no differences in subjective quality of life in each group based on average levels of secondary control. However, when the five types of secondary control were analysed separately some differences were apparent. Ventilation negatively predicted the subjective quality of life of the three groups. Avoidant secondary control predicted for people with MS and situation bias secondary control positively predicted for controls. An interaction effect between group membership and situation bias secondary control was also evident. Partners reported a higher subjective quality of life at conditions of high situation bias secondary control. However, when the three groups were compared people with
MS fared significantly worse than the other two groups at high levels of situation bias secondary control.
In regards to primary control, people with MS reported a lower subjective quality of life compared to the other two groups at levels of high primary control in
5 support of the hypothesis. However, in contrast with expectations, partners reported a higher subjective quality of life at high levels of primary control, and primary control did not predict the subjective quality of life of controls.
Hypothesis 9: 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.
In order to address this hypothesis, the effect of three levels of relative primary and secondary control on subjective quality of life were compared: low primary, low secondary; high primary, high secondary, and an ‘unbalanced’ condition

6 where either primary or secondary control was favoured. In contrast with the hypothesis, the analyses revealed no difference in subjective quality of life within each group between these levels of control. However, when the three groups were compared, people with MS fared worse than the other two groups at balanced levels of control, and worse still at levels of high primary and high secondary control. The hypothesis was not supported.
The adaptiveness of within-couple coping could not be explored due to the low number of matched couples who took part.
Discussion
This study aimed to investigate the validity a model proposed to explain the maintenance of subjective quality of life by exploring the inter-relationships between the variables of the model in three different groups: people with MS, partners of people with MS and a control comparison group. The model, based largely on previous research, proposed that personality, positive cognitive biases and perceived social support influence subjective quality of life. The model also hypothesised that secondary control mediates the relationship between positive cognitive biases and subjective quality of life. The findings of this study will now be discussed in relation to the previous research discussed in the first five chapters of the thesis, possible avenues for future research and to potential interventions aimed at improving subjective quality of life.
The Proposed Model for the Maintenance of Subjective Quality of Life
The findings of this study support the proposed model for the maintenance of subjective quality of life. Cummins and Cahill’s (in press) hypothesised link between personality, positive cognitive bias and subjective quality of life, and the inclusion of perceived social support and secondary control into the model proposed by this thesis were supported. The variables of the model accounted for a significant portion of the subjective quality of life for each group (45 % for controls, 59% for people with MS and 58% for partners of people with MS). The

contribution of the psychological variables of the model to subjective quality of life is supportive of the assertion that life circumstances only exert a limited influence on subjective quality of life (Argyle, in press).
7
While psychological variables: personality, positive cognitive biases, perceived social support and secondary control, predicted a large proportion of the subjective quality of life of the three groups in the study, as hypothesised people with MS reported a lower subjective quality of life than both partners and controls. Thus, for people with MS life circumstances exerted a powerful influence on their subjective quality of life. This is consistent with Cummins’
(2000) assertion that the psychological mechanism that maintains subjective quality of life can be defeated by chronic life conditions that impose a burden that is too strong to allow for adaptation.
The lowered subjective quality of life of people with MS is supportive of previous research (Canadian Burden of Illness Study Group, 1998; Gulick, 1997; Nortvedt et al., 1999). However, partners in this study did not report a lowered subjective quality of life compared to controls. This finding is inconsistent with previous research that has found lowered subjective quality of life in partners of people with MS (Pakenham, 1997) and carers of chronically ill people (Cummins, 2001).
Partners in this study therefore functioned better than partners in other research.
There may be several reasons for this discrepancy. The findings may be due to the low number of partners who took part in the study (n = 37) that likely weakened the strength of analysis. Alternatively, the recruitment of partners through people with MS may have resulted in a biased sample of partners. People with MS may not have included low functioning partners in the study.
Despite the similarity between the subjective quality of life of partners and controls, the variables of the model interacted differently between the two groups, which further differed from people with MS. The interactions between personality, positive cognitive biases, secondary control, perceived social support and subjective quality of life for each group are now discussed.

8
Personality
The impact of personality on subjective quality of life did not largely vary between the three groups. As hypothesised, neuroticism, and to a lesser extent extraversion, predicted the subjective quality of life of people with MS, partners and controls. This finding is consistent with previous research (Francis & Bolger,
1997; Gurizerath et al., 2001; Hyland et al., 1994; McCrae & Costa, 1991;
Pastuovic et al., 1995; Yamaoka et al., 1998).
People with MS were less extraverted than the other two groups in the study, and the variation in extraversion was attributable to three items of the NEO Five-
Factor Inventory that were likely reflective of illness symptomatology. The effect of life circumstances (MS) on extraversion found by the study is inconsistent with previous research that found that personality traits were stable and had strong genetic links (Tellegen et al., 1998). The effect of MS on extraversion suggests that either the genetic component of personality has been overestimated in previous research and that life circumstances can effect personality, or that current personality inventories are biased towards people with illness symptoms indicative of certain personality traits in healthy people. The stability of personality has implications for future research as stability renders personality an ineffective target for intervention. Further research is needed to explore the stability of personality, especially in relation to people with illness.
Positive Cognitive Biases
The influence of positive cognitive biases of self-esteem, optimism and primary control on subjective quality of life varied between the three groups. The differences between the three groups are now discussed. The role of primary control in relation to secondary control is then discussed in-depth.

9
Self-Esteem
Consistent with Taylor and Brown’s (1988) assertion, and with hypotheses of the thesis, self-esteem was positively associated with the subjective quality of life of the three groups. This association suggests that people who felt good about themselves also felt good about the rest of their lives. However, the high association between subjective quality of life and self-esteem evident in this study also suggests that they may be part of a unitary construct. As such, the inclusion of self-esteem in a model predicting subjective quality of life is arguably superfluous and warrants further investigation.
As hypothesised, consistent with a lowered subjective quality of life, people with
MS also reported a lowered self-esteem compared to the other two groups. The lowered self-esteem of people with MS is consistent with previous research
(Brooks & Matson, 1982). Previous research suggests some mechanisms by which positive cognitive biases, of which self-esteem is one, are maintained.
These mechanisms may explain the lowered self-esteem of people with MS. The potential physical and psychosocial impairments experienced by people may result in frequent failure experiences, which have been proposed to maintain the upper boundary of positive cognitive bias (Cummins & Nistico, in press), and may therefore explain the lowered self-esteem of people with MS. In addition, this thesis asserted, based on Wiesz et al.’s (1984) definition of secondary control, that secondary control maintains the lower boundary of positive cognitive bias. In accordance with this proposed role of secondary control, the study found that the use of secondary control by people with MS was negatively associated with subjective quality of life. It is likely therefore that the lowered self-esteem found in people with MS in this study resulted from a relatively high incidence of failure experiences, which lowered the upper boundary, and of the functioning of secondary control, which did not sufficiently raise the lower boundary of positive cognitive bias. Thus, self-esteem could be effectively targeted by interventions that focus on reducing failure experiences and improving the adaptive functioning of secondary control.

10
Optimism
Contrary to biases of self-esteem and control, it was expected that optimistic bias would be larger in people with MS due to the unpredictable nature of their illness.
This expectation was based on Robinson and Ryff’s (1999) assertion that selfdeception is greatest under conditions of information uncertainty and high motivation, and that an absence of relatively concrete information about the future provides an ideal opportunity for envisioning the best possibilities for one’s self.
In contrast with this proposal, greater optimistic bias was not found in the people with MS in this study. This is inconsistent with Fournier et al’s. (1999) research that found significant optimistic bias in people with MS. However, Fournier et al. did not compare their findings to people without chronic illness. The findings of this thesis suggest that the optimism found in their sample of people with MS likely reflected the tendency for optimism in all people (Brown, 1986).
The absence of increased optimistic bias in people with MS may due to constraints imposed by their illness. There may be sufficient concrete information about the future to prevent high optimistic bias. For example, while the course of
MS is largely unpredictable, deterioration in health is very likely (Rao et al.,
1992). However, such negative information regarding the future would possibly have a negative impact on optimistic bias. Perhaps both positive and negative influences may impact optimistic bias, such that together they serve to maintain the optimistic bias of people with MS at normal levels. Further research is needed to investigate the influences on the optimistic bias of people with illness.
The influence of optimism on subjective quality of life varied between the three groups. In support of previous research optimism positively predicted the subjective quality of life of the control group (Aspinwall & Taylor, 1992).
Optimism did not predict the subjective quality of life of either people with MS or partners. This finding is inconsistent with previous research that found a relationship between optimism and well-being for people with MS (Fournier et al.,
1999). However, no research was located that had investigated the relationship

11 between optimism and subjective quality of life in partners of people with MS or other chronic illness.
Optimism may have exerted its effect on subjective quality of life through coping efforts for people with MS and partners that was not detected by the study. For example, Scheier, Weintraub and Carver (1986) found that optimists tend to adopt strategies that are more effective when coping with stress. This was not explicitly tested by the study and is an avenue for future research. However, the lack of association between optimism and the subjective quality of life of people with MS and their partners suggests that optimism would be an ineffective target for interventions aimed at improving subjective quality of life.
Primary Control
Unexpectedly, despite the potential restraints on beliefs in personal competence for people with MS due to disability, there were no differences between the three groups in the level of primary control. While, primary control negatively predicted the subjective quality of life of people with MS, partners’ subjective quality of life was positively predicted by primary control, and primary control had a negligible impact on the subjective quality of life of controls. Thus, while people with MS were able to maintain beliefs in personal competence, high levels of these beliefs had a negative impact on their well-being, and those who had low beliefs in personal competence were more satisfied with their lives than those with high beliefs in personal competence. The negative impact of primary control on the subjective quality of life of people with MS is in direct contrast to the
Primacy/Back-Up Model of control (Heckhausen & Schulz, 1995) that claims that primary control is more adaptive than secondary control regardless of the controllability of the situation.
The negative relationship between subjective quality of life and primary control for people with MS was hypothesised by the thesis and is supported the
Discrimination Model of control that claims that primary control is only adaptive when the situation is controllable (Folkman, 1984; Thompson et al., 1998). The

finding is also supportive of the majority of previous research of other ill people
12 including those with Rheumatoid Arthritis (Affleck et al, 1987), cancer (Burish et al, 1984) and end-stage renal disease (Eitel et al., 1995). These findings suggest that people with MS would benefit from reduced beliefs in personal competence.
If it is assumed that partners experience less uncontrollable situations than people with MS, then the positive impact of primary control on the subjective quality of life of partners is also supportive of the Discrimination Model. Partners were positively effected by primary control. Thus, in more controllable life circumstances primary control was adaptive. Partners would benefit from interventions that focused on increasing their feelings of personal competence.
The Discrimination Model would predict that primary control is most adaptive for people under no stress however, inconsistent with this prediction, the subjective quality of life of the control group was unaffected by the use of primary control.
In summary, the adaptiveness of primary control depended on the controllability of life circumstances. For people presumably experiencing the most uncontrollable situations, people with MS, primary control was negatively predicted of subjective quality of life. For people experiencing less uncontrollable situations, partners, primary control had a positive effect on subjective quality of life. The subjective quality of life of people presumably experiencing the least uncontrollable situations, controls, was unaffected by primary control. These findings suggest primary control effects subjective quality of life only under stressful conditions, and that the adaptive function of primary control in stressful condition is explained by the Discrimination Model of control (Folkman, 1984;
Thompson et al., 1998). The Discrimination Model relates the adaptive outcome of primary control to the controllability of situations. Further research would therefore benefit from exploring the adaptive role of primary control in relation to the controllability of specific life circumstances.

13
The Mediating Role of Secondary Control
As hypothesised, secondary control mediated the relationship between positive cognitive biases and subjective quality of life for people with MS, their partners and, to a lesser extent, controls. Thus, the proposal that secondary control interacts with other psychological variables in a predictable way, and its inclusion in the model for the maintenance of subjective quality of life was supported. It was hypothesised that life circumstances can challenge the positivity of cognitive biases and that secondary control acts to accommodate such stressors so that subjective quality of life is maintained. This hypothesis was based on the definition of secondary control as accepting or adjusting to one’s situation (Wiesz et al., 1984).
Consistent with the reactive role of secondary control hypothesised by this thesis, secondary control mediated the effect of positive cognitive biases on subjective quality of life to differing extents for each group. Secondary control mediated to the greatest extent for people with MS, less so for partners and least for controls.
Thus, the impact of secondary control seemed to be associated with the degree of stress experienced, with the greatest impact associated with people with MS.
The role of secondary control was apparent only when the five types of secondary control were analysed separately. Ventilation, avoidant and situation bias secondary control were negatively associated with subjective quality of life of people with MS. They also used avoidant secondary control more than the other two groups. Thus, people with MS were using secondary control in ways that were negatively associated with their well-being. The high use of avoidant coping and its negative relationship with well-being for people with MS is supportive of previous research (Aikens et al., 1997). The maladaptive outcome of secondary control for people with MS is inconsistent with the Discrimination Model, which claims that perceptions of secondary control, rather than primary, are adaptive when the situation is uncontrollable.

14
The effect of secondary on the subjective quality of life of partners varied.
Ventilation negatively predicted and situation bias positively, predicted subjective quality of life. The effect of secondary control on the subjective quality of life of controls was negligible.
Thus, as with primary control, the adaptive outcome of secondary control was related to the controllability of life situations. The use of secondary control was maladaptive for people with MS. For partners, the adaptive outcome of secondary control was mixed, and for controls there was negligible impact of secondary control on subjective quality of life. The functioning of secondary control was not consistent and did not support any of the three models proposed to explain that adaptive outcome of primary and secondary control. However, these findings suggest that secondary control efforts to accept or adjust to life situations have the most impact on subjective quality of life in times of stress.
As was asserted by the authors of the Primary and Secondary Control Scale
(Maher et al., 2001), this study highlighted the importance of analysing the five types of secondary control separately due to their different functional purposes.
The findings of this study clearly demonstrated that secondary control does not have a unitary function, and therefore suggest that the primary and secondary control distinction may be too simplistic. Current models based on the primary and secondary control distinction (i.e. the Discrimination Model (Folkman, 1984;
Thompson et al., 1998), the Primacy/Back-Up Model (Heckhausen & Schulz,
1995)) do not adequately describe the varied functions of secondary control.
Further research is needed to generate theories regarding the adaptive outcome of secondary control.
These findings suggest some possibilities for interventions. People with MS would likely benefit from reduced avoidant secondary control. Interventions may focus on assisting people with MS to find more adaptive ways to cope with life difficulties rather than avoiding them. Unfortunately, the findings of the study did not demonstrate any positive coping strategies for people with MS. Partners of

15 people with MS would likely benefit from interventions aimed at assisting them to see positive aspects to difficult experiences.
The Adaptive Outcome of Primary and Secondary Control
The adaptive outcome of primary control supported the Discrimination Model of control (Folkman, 1984; Thompson et al., 1998) that claims that primary control is adaptive when the situation is controllable. However, the adaptive outcome of secondary control did not support the Discrimination Model of control that also claims secondary control is adaptive when the situation is uncontrollable. The
Primacy/Back-Up Model (Heckhausen & Schulz, 1995) that claims that primary control is adaptive regardless of the controllability of the situation and Heep’s
(2000) assertion that balanced levels of high primary and high secondary control are related to high subjective quality of life were not supported either. Thus, current models of the adaptive outcome of primary and secondary control did not describe the functioning of primary and secondary control evident in this study.
There may be some explanations for these findings.
Adaptive primary and secondary control functioning of individuals may be effected by the relationship between partners’ coping. Previous research suggests that couples tend to react to disease as a unit, such that their use of coping strategies is matched (Pakenham, Dadds & Terry, 1995). While there were insufficient numbers of matched couples (n = 10) to explore processes operating within couples, the findings of the study provide some clues to the adaptiveness of coping within couples. Previous research suggested that the similarity of coping between partners and the couple’s average levels of coping are positively associated with well-being (Pakenham, 1998; Revenson, 1994). However, the findings of this thesis suggest that for people with MS dissimilarity, rather than similarity, between couples may be adaptive. Specifically, well-being may be associated with the use of high primary control in partners and the use of low primary control in partners. Thus, the adaptive functioning of the primary and secondary control of couples effected by illness may be different than that of other

16 couples such that, the adaptive outcome of individual’s use of primary and secondary control is related to their partners’ use of primary and secondary control. Intra-couple processes may explain the adaptive outcome of primary and secondary control evident in this study and could be explored further in future research.
It is also possible that the maladaptiveness of primary and secondary control for people with MS evident in the study was a product of the types of difficulties they faced and chose to cope with rather than the use of control per se. This has been demonstrated in research with other chronically ill people. For example, for people with Rheumatoid Arthritis perceiving control over some parts of their illness was adaptive, but perceiving control over other parts was maladaptive
(Affleck et al., 1987). Perhaps people with MS would similarly benefit from focusing their primary control on more controllable aspects of their lives. Further research needs to explore the adaptive outcome of primary and secondary control in regards to the specific types of difficulties people with MS and their partners experience to this end.
Future research would also benefit from a longitudinal design that could explore changes in primary, secondary control and subjective quality of life over time and thus determine causality. It may be that low levels of subjective quality of life causes high levels of primary and secondary control. People with lowered subjective quality of life may engage in high levels of both primary and secondary control in an attempt to manage their lowered subjective quality of life, albeit unsuccessfully. The functioning of primary and secondary control found in this study may not predict subjective quality of life over time. However, as Lazarus
(1993) claims: there may be no universally good or bad coping processes.
Social Support
As hypothesised, perceived social support was positively predictive of the subjective quality of life of all three groups. This finding is supportive of previous research that found perceived social support to be positively associated with the

17 well-being of both people with illness (Germano, 1996; Holohan et al., 1996;
Weinert, 1988) and people without illness (Abbey et al., 1985; Schaefer, Coyne &
Lazarus, 1981).
The social activities of people with MS are likely to be compromised by reduced access to employment (O’Brien, 1993) and the symptoms of their illness (Bartels
Des Rosier et al., 1992). Unexpectedly, despite the potential constraints on the social activities of people with MS, they did not report reduced perceived social support from people. Consistent with the threshold effect of perceived social support proposed by Cohen and Wills (1985) and found by Abbey et al. (1985), people with MS also felt the absence of perceived social support more than controls. The finding of a threshold effect suggests that, despite their relatively high levels of perceived social support, people with MS would likely benefit from interventions targeted at increasing social support. Interventions need not only to increase social contact but also to improve the quality of existing social supports as perceptions of available support rather than the use of social support are related to well-being (Cunningham McNett, 1987; Schaefer, Coyne & Lazarus, 1981).
Also, both the positive and problematic aspects of support need to be considered
(Holahan et al., 1996; Revenson et al., 1991). Further research is needed to explore the support needs of people with MS.
As expected, perceived social support from pets also played an important role in the maintenance of subjective quality of life for people with MS. This finding is consistent with Study One, in which participants cited pets as an important source of support and influence on their subjective quality of life. In the second study, perceived social support from pets negatively predicted the extent to which people with MS perceived that their illness effected their life role that subsequently positively predicted subjective quality of life. Thus, interventions aimed at increasing social support from pets would likely be beneficial for people with MS.
Even though partners presumably have more opportunities for social activities outside the home than people with MS, they reported lower perceived social

support than both controls and people with MS. Further research is needed to determine why partners perceived less social support than controls and people with MS. There are a number of possible reasons. While both the person with
18
MS and their partner likely spend more time with each other at home and less time in network relationships and activities outside the home (Bartels DesRosier et al.,
1992), partners may receive less support because family and friends focus their support on the person with MS and neglect the partner. Also, as demonstrated in
Study One, people with MS are likely to received additional formalised support from health professionals. Alternatively, the quality of support may be reduced for partners. For example, they may perceive less support within intimate relationships. While the person with MS has a healthy partner who they can to turn for support, the partner may not feel able to request support from their ill partner. This is evidenced by the lower relationship satisfaction reported by partners of people with MS compared to people with MS in previous research
(Dupont, 1996). Expectations regarding support may also differ between partners and people with MS such that people with MS are satisfied with less support than partners. Improved understanding of causal factors is crucial in order that interventions are effectively targeted.
In summary, the findings of the study revealed some differences between the functioning of people with MS, partners and controls that have several implications for future research and interventions. The strengths and limitations of the study are now discussed.
Strengths and Limitations of the Study
The major strengths of this study were the use of a generic model for predicting subjective quality of life and the use of comparison groups. The use of comparison groups yielded many findings that would have not been apparent if only one group of people was investigated. For example, the adaptive outcome of primary control was only apparent when groups of individuals faced with different life circumstances were compared. The threshold effect of perceived social support was also only apparent when groups of people subject to different levels

19 of stress were compared. Comparison with a control group also informed recommendations for interventions. With the control group as a baseline, impairments in the functioning of other groups could be identified. For example, while partners’ subjective quality of life was not reduced compared to controls, analysis of interactions between the variables of the model indicated that they maintained their subjective quality of life in different ways than control. For example, beliefs in personal competence were a strong predictor of the subjective quality of life of partners by not controls. Comparisons also revealed that they experienced reduced perceived social support that potentially placed them at risk of lowered subjective quality of life due to its close association with subjective quality of life.
The study was limited by the relatively small sample size, in particular of partners.
This necessitated the use of less than optimal data analysis techniques in some instances. For example, the size of the sample precluded the use of structural equation modeling. Also, exploration of couple coping was not possible due to small number of matched couples who took part. The small sample size also restricted the generalizability of the findings. For example, the illness status information obtained from participants suggests that the sample was likely experiencing illness remission rather than exacerbation, and had not experienced a great deal of illness deterioration in the past year. A more representative sample including individuals experiencing illness deterioration may reveal differences in subjective quality of life associated with illness status, and would likely also provide more variability within which to explore the adaptive outcome of primary and secondary control.
This small sample size occurred despite extensive recruitment efforts. This may be due to difficulties in recruitment inherent to the nature of the sample. For example, physical and cognitive impairments may dissuade individuals from taking part. Also, the unpredictable nature of their illness may prevent them from committing to a research project. Future research with this population would benefit from a more protracted recruitment process with a particular focus on

20 recruiting those in periods of illness exacerbation. This would hopefully result in a larger more representative sample of people with MS and their partners.
Conclusion
The findings of this study support model proposed by this thesis for the maintenance of subjective quality of life. The previously hypothesised link between personality, positive cognitive bias and subjective quality of life was supported (Cummins & Cahill, in press). In addition, the integration of perceived social support and secondary control into the model hypothesised by this study was supported. The model was valid for all three groups. People with MS reported a lowered subjective quality of life compared to partners and controls.
As predicted, despite the similarity between partners and controls, the interactions between the variables of the model varied between the two groups, which further varied from people with MS. The findings supported the validity and utility of a model for subjective quality of life applicable to groups of people in different life circumstances that enables meaningful comparisons. Recommendations for future research and interventions were made. The next chapter provides an overview of the thesis and conclusions.