Psychophysiological Response to Stress: A Potential Mediator of Negative Urgency and Alcohol Use
Erin Walsh, M.S., Karen Derefinko, Ph.D., Richard Milich, Ph.D. & Don Lynam, Ph.D.*
Department of Psychology, University of Kentucky
*University of Purdue, Department of Psychological Sciences
Purpose. This study investigated the role of stress in the Negative Urgency-alcohol
relation. Specifically, psychophysiological response to stress was examined as a
potential mediator of Negative Urgency and alcohol consumption patterns.
Participants.
Participants (N=223) were introductory psychology students from the University
of Kentucky.
Methods. Participants (N=223) were introductory psychology students. Participants
completed self-report measures assessing personality traits related to impulsive
behavior, as well as alcohol consumption patterns from the age of 13 to the time of
testing. Participants were then exposed to a computerized arithmetic task known to
cause emotional distress. Level of sympathetic arousal, as measured by cardiac preejection period (PEP), was assessed at three separate time points: Pre-Task Baseline;
Stressor; Post-Task Recovery.
Self-Report Measures.
UPPS Impulsive Behavior Scale (UPPS; Whiteside & Lynam, 2001). The UPPS is
a 45-item measure assessing four distinct personality pathways to impulsive
behavior: Negative Urgency, (lack of) Premeditation, (lack of) Perseverance, and
Sensation-seeking. For the present analyses, only Negative Urgency was used.
Results. Negative Urgency positively correlated with periods of alcohol use and heavy
alcohol consumption. Negative Urgency was also significantly related to cardiac PEP
at Pre-Task Baseline and Post-Task Recovery periods. Contrary to predictions, cardiac
PEP was unrelated to patterns of alcohol use. Due to null findings, the proposed
mediation was not tested.
Discussion. These findings suggest that individuals high in Negative Urgency
experience increased sympathetic arousal in resting states and may have difficulty
recovering from stressful events. However, psychophysiological response to stress
may not be the mechanism which leads to maladaptive alcohol use in those high in
Negative Urgency. Possible explanations are offered for this finding.
INTRODUCTION
•
•
Negative Urgency, or the tendency to act rashly under conditions of negative
affect, strongly predicts alcohol use, dependence, and addiction-related problems
(Whiteside & Lynam, 2003; Verdejo-Garcia et al., 2007; Fischer & Smith, 2008).
Individuals high in Negative Urgency may struggle with executive processes such
as risk evaluation and inhibition in the presence of negative affect (Kaiser et al., in
prep).
•
•
•
The temporary relief from negative affect when using substances, which
increases the likelihood of future use (Fischer & Smith, 2008), may explain the
ability of Negative Urgency to predict substance use and dependence.
Although many studies have examined the link between stress and alcohol use, few
have explored what role, if any, Negative Urgency plays in this relation. Given
that stressful situations often evoke negative emotions and overwhelming physical
sensations, this particular facet seems particularly relevant to this area of study.
The purpose of the present study was to investigate the role of stress in the
Negative Urgency-alcohol relation. The following predictions were made:
1. Negative Urgency will positively correlate with alcohol use and abuse.
2. Negative Urgency will positively correlate with sympathetic nervous system
(SNS) activity during a stressful laboratory task.
3. Psychophysiological response to stress will mediate the relation between
Negative Urgency and alcohol consumption patterns.
Life-History Calendar (LHC; Caspi et al., 1996). The LHC is a data-collection
method that asks participants to retrospectively recall life events and behaviors. The
LHC uses a grid to document the occurrence of particular events in a participant’s
life.
For the present study, we used the LHC to assess alcohol consumption patterns
from the age of 13 to the time of testing. Specifically, we examined the total number
of periods in which a participant reported any alcohol use or heavy alcohol use (i.e.,
five or more drinks).
Physiological Measures.
Cardiac Pre-Ejection Period (PEP). PEP is an index of sympathetic cardiac
control. Shortened PEP is reflective of greater sympathetic nervous system (SNS)
influence. PEP was assessed at three separate time points:
•Pre-Task Baseline
•Stressor
•Post-Task Recovery Period
Laboratory Task.
Paced Auditory Serial Addition Task-Computerized Version (PASAT-C; Lejeuz et
al., 2003). The PASAT-C is a computerized arithmetic task known to induce
emotional distress. In this task, numbers are sequentially presented on a computer
screen. Participants are asked to add each newly presented number to the previously
displayed number. The task consists of three levels which progress in difficulty. For
the present study, we defined our “Stressor” as a one-minute period when latency
between number presentations first decreased.
NegUrg
NegUrg
1
Baseline
PEP
Stressor
PEP
Recovery
PEP
AlcUse
AlcHeavy
-.13*
1
.03
.30**
3. Contrary to expectations, sympathetic activity (as assessed by cardiac PEP)
decreased in response to a stressor. This indicates that the PASAT-C did not
evoke a stress response in the present sample.
4. There were no relations between cardiac PEP at any specified time point and
patterns of alcohol use. As the observed findings did not meet criteria to test
meditational hypotheses, the proposed mediation was not tested.
Recovery AlcUse
PEP
AlcHeavy
DISCUSSION
Findings and Implications.
1. Negative Urgency was strongly related to periods of alcohol use and heavy alcohol
consumption.
2. Negative Urgency was also positively associated with cardiac PEP at Baseline and
Recovery periods.
1
-.13*
.82**
-.01
1
.15*
.16**
.07
.04
.09
.07
.05
.04
•
1
.59**
These results suggest that individuals high in Negative Urgency experience
increased sympathetic arousal in resting states and may have difficulty recovering
from stressful events.
1
3. Contrary to predictions, psychophysiological response to stress did not mediate the
relation between Negative Urgency and patterns of alcohol use. Specifically, SNS activity
at all time periods (as assessed by cardiac PEP) was unrelated to alcohol use or abuse.
Note. NegUrg= Negative Urgency, from UPPS Impulsive Behavior
Scale (Whiteside & Lynam, 2001). PEP=Cardiac Pre-Ejection Period.
AlcUse=Period of any alcohol use. AlcHeavy= Period of heavy alcohol
use, from Life History Calendar (Caspi et al., 1996).
•
The following explanations are offered for this unexpected finding:
•
SNS activity may not mediate the relation between Negative Urgency and patterns
of alcohol use.
•
Individuals high in Negative Urgency may experience decreased impulse control in
domains other than alcohol use when experiencing strong or “unpleasant”
physiological sensations. That is, SNS response to stress may mediate the relation
between Negative Urgency and other maladaptive behaviors (e.g., self-injury).
•
Underage college students, such as those in the present sample, may lack sufficient
exposure to the negatively-reinforcing effects in question to acquire strong patterns
of maladaptive alcohol use.
•
The PASAT-C may be an insufficient stressor. As seen in Figure 2, the change in
cardiac PEP from Pre-Task Baseline to Stressor is in the opposite- expected
direction. This suggests that participants may not have experienced high levels of
distress during the task.
Figure 1. Cardiac PEP as a Function of Negative Urgency:
Expected Finding
PEP as a Function of Negative Urgency: Expected Finding
Low Neg Urg
Avg Neg Urg
High Neg Urg
Future directions.
Baseline
Stressor
1. Consider the use of alternative laboratory stressors, such as personalized vignettes
(Sinha et al., 2004) or aversive pictures (Colder, 2001).
Recovery
2. Explore relations between Negative Urgency, alcohol use, and parasympathetic nervous
system (PNS) reactivity to stress.
Figure 2. Cardiac PEP as a Function of Negative Urgency:
Obtained Finding
1. As predicted, Negative Urgency significantly correlated with self-reported
periods of alcohol use and heavy alcohol consumption.
2. Negative Urgency also showed strong significant relations with cardiac PEP at
Pre-Task Baseline and Post-Task Recovery periods.
Stressor
PEP
** p < .01 * p < .05
Procedure.
Participants were enrolled in a larger study examining multiple predictors of
substance use. The 2.5 hour protocol entailed administration of various self-report
questionnaires, behavioral measures, and a psychophysiological assessment.
RESULTS
Baseline
PEP
SNS Arousal
METHOD
3. Examine if SNS/PNS-response to stress mediates relations between Negative Urgency
and other types of substance abuse or other types of maladaptive behavior.
PEP as a Function of Negative Urgency: Obtained Finding
ACKNOWLEDGEMENTS
SNS Arousal
ABSTRACT
Table 1.
Correlations between Negative Urgency, Cardiac PEP, and
Alcohol Consumption Patterns.
Low Neg Urg
Research supported by: NIDA DA005312
Avg Neg Urg
High Neg Urg
Baseline
Stressor
Recovery
Thanks to Mark Fillmore, Ph.D. for poster sponsorship.
Correspondence concerning this poster can be sent to Erin Walsh, University of Kentucky.
Email: edubwalsh@gmail.com