The association of excessive alcohol use with public health problems and mortality underscores the importance of examining factors that impact alcohol use (Room et al. 2005
). Stress and impulsivity are associated with increased drinking behavior (Evenden and Ryan 1999
; Sinha 2008
; Lejuez et al. 2010
), and stress may also act via impulsivity to influence alcohol consumption (Fox et al. 2010
). Stress has been associated with increases in impulsivity (Glass and Singer 1972
; Cohen 1980
; Muraven and Baumeister 2000
; Sinha 2001
; Tice et al. 2001
). Because stress has been associated with increases in impulsivity, and impulsivity is associated with increased alcohol use, impulsivity may mediate the effect of stress to increase alcohol use. Determining whether impulsivity mediates the stress and alcohol use relationship is important for treatment and prevention efforts. If impulsivity mediates the effect of stress to increase alcohol use, then treatments targeted to reduce impulsivity may diminish the effect of stress on hazardous drinking.
In the past decade, research attention has focused on impulsivity because of its role in detrimental behaviors, including excessive alcohol use (Lejuez et al. 2010
). Impulsivity, a tendency to act rapidly with diminished regard for future consequences, can be inferred psychometrically from responses on self-report questionnaires and behaviorally from responses on laboratory tasks (Moeller et al. 2001
; Lane et al. 2003
; Reynolds et al. 2006
). Choice impulsivity is indexed behaviorally by a diminished ability or willingness to delay gratification on behavioral tasks that measure delay of reward. Response impulsivity, on the other hand, is indexed behaviorally by a diminished ability to inhibit prepotent responses on behavioral response inhibition tasks. Self-reported impulsivity does not always correlate or factor with either type of behavioral impulsivity (Lane et al. 2003
; Meda et al. 2009
). Furthermore, the two types of behaviorally assessed impulsivity do not typically correlate with each other (Lane et al. 2003
; Reynolds et al. 2006
), suggesting the measures may assess different impulsivity dimensions. The dimension of impulsivity captured by self-report measures may reflect a characteristic that individuals are able to identify in their own behavior (Lane et al. 2003
), while the behavioral impulsivity laboratory tasks assessing individuals’ ability to inhibit a response or to delay gratification at the time of measurement rely less on self-perception. The effect of stress on drinking behavior may be differentially mediated by the various dimensions of impulsivity, and knowledge of such differences could result in improved treatment and prevention strategies for individuals based on their impulsivity characteristics.
Different types of impulsivity were associated with different stages of alcohol use, abuse, and dependence (Lejuez et al. 2010
). Early alcohol use was related to greater delay discounting, poorer response inhibition, and increased self-reported impulsivity (Lejuez et al. 2010
). Current and early problem alcohol use and alcohol use disorders were associated with greater delay discounting and self-reported impulsivity (Lejuez et al. 2010
). Hazardous drinking, a type of excessive drinking related to public health problems (Room et al. 2005
), also was associated with self-reported impulsivity (Hamilton et al. in press
Longitudinal studies are valuable in examining changes in alcohol use that correlate with changes in impulsive tendencies. In a longitudinal study that followed men and women from the ages of 18–35, decreases in self-reported trait impulsivity were associated with decreases in problematic alcohol use (Littlefield et al. 2010
). From this large sample, five trajectory groups were identified that differed in baseline levels of self-reported impulsivity and developmental patterns of change. Interestingly, the trajectory group that demonstrated the sharpest decline in the trait also had an accelerated decrease in alcohol use from ages 18 to 25 (Littlefield et al. 2010
). In a longitudinal study of Alcoholics Anonymous participants, decreases in self-reported trait impulsivity mediated reductions in alcohol-related problems (Blonigen et al. 2011
). In light of these findings, it is conceivable that self-reported impulsivity may mediate the effect of stress on alcohol use.
Stress is experienced when organisms perceive that a challenge exceeds their resources for coping (Baum et al. 1997
), setting in motion a cascade of physiological events involving the hypothalamic–pituitary–adrenal axis and the sympathetic nervous system in an attempt to regain homeostasis (McEwen 2000
). Cumulative stress is a risk factor that can increase individual vulnerability for a wide range of addictive behaviors (Sinha 2008
). Physiological responses to stressors may alter brain motivational pathways, such as those involving the medial prefrontal cortex, a region implicated in self-control and the inhibition of impulses (Arnsten and Goldman-Rakic 1998
; Sinha 2008
). Over time, such neurobiological alterations may predispose individuals to a behavioral style characterized by increased impulsiveness, which could lead stressed individuals to engage in addictive behaviors like alcohol consumption (Sinha 2008
). The effects of stress on the neurobiology of impulse control support the possibility that impulsivity may mediate the relationship between stress and alcohol use, a possibility that has not been previously examined.
Longitudinal studies of stress and alcohol use provide empirical support for a role for stress in alcohol use. In a sample of university students followed longitudinally during their transitional year after graduation, higher levels of perceived stress and stressful life events predicted greater consumption of alcohol and a greater frequency of intoxication (Sadava and Pak 1993
). A variety of socially relevant stressful life events increase drinking (Veenstra et al. 2006
). The transitions of both retirement (Perreira and Sloan 2001
) and divorce (Romelsjo et al. 1991
; Perreira and Sloan 2001
) were associated with increased alcohol use in two large samples of men and women followed longitudinally. Marital stress (Brennan et al. 1999
) and becoming widowed (Perreira and Sloan 2001
) were associated with increased alcohol use in men, while moving away from a friend or the death of a friend were associated with increased drinking in women (Glass et al. 1995
). In addition, financial stressors and more negative life events were associated with increased drinking in women (Brennan et al. 1999
). Interestingly, some types of stressors, particularly health-related stressors, were associated with decreased alcohol consumption (Glass et al. 1995
; Brennan et al. 1999
). For this reason, it is important to consider stressor type when examining the relationship between stress and alcohol use. Although it was not examined in these studies, it is possible that elevated impulsivity mediated the relationship between stress and increased alcohol use reported in many experiments.
To examine mediation, statistical associations may be used within a cross-sectional sample to determine statistically whether associations with retrospectively assessed stressful life events support theoretically predicted relationships. Although the cross-sectional design does not allow for the examination of impulsivity, stress, and alcohol use over time, associations of stress and impulsivity with alcohol use have been established in studies with longitudinal designs. For this reason, it is reasonable to model retrospective reports of stressful life events over the course of the lifespan, as measured in the present study, and examine their relationships to impulsivity and alcohol use.
The present research was conducted to determine whether self-reported impulsivity, choice impulsivity, and response impulsivity statistically mediate the effects of stress on alcohol use. Self-reported impulsivity was assessed using the Barratt impulsiveness scale, version 11 (BIS-11), choice impulsivity was assessed by performance on the experiential discounting task (EDT), and response impulsivity was assessed by performance on the go/no-go task (GNG) in a community-based sample of 192 men and women. Based on previous research in which self-reported impulsivity and choice impulsivity were associated with current alcohol use, early alcohol problems, and alcohol use disorders (Lejuez et al. 2010
), it was hypothesized that self-reported impulsivity and choice impulsivity, but not response impulsivity, would statistically mediate the effect of stress on alcohol use (see ).
Mediation model of stress, impulsivity, and drinking behavior.