Impulsivity as a mediating factor in the association between posttraumatic stress disorder symptoms and substance use.

OBJECTIVE: Posttraumatic stress disorder (PTSD) has been associated with heightened impulsivity and risk-taking behaviors, including higher rates of substance use than individuals without PTSD. Although a number of studies suggest that impulsivity is associated with substance use in PTSD, the specific role of impulsivity in this common pattern of comorbidity remains unclear. The current study investigated associations between PTSD symptoms, substance use patterns, and impulsivity in a sample of adults. METHOD: A total of 2,967 participants were recruited online through Amazon's Mechanical Turk. Participants who did not report at least one Criterion A traumatic event on the Brief Trauma Questionnaire were excluded. The remaining 1,609 trauma-exposed individuals were placed into either the probable PTSD group (n = 406) or the trauma-exposed non-PTSD group (n = 1,203) based on their PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders, fifth edition (PCL-5) score. Impulsivity was assessed via a delay discounting measure and the brief UPPS-P (urgency, premeditation, perseverance, sensation seeking, and positive urgency) Impulsive Behavior Scale. Alcohol and cannabis were assessed using the Alcohol Use Disorders Identification Test (AUDIT) and Cannabis Use Disorders Identification Test (CUDIT-R) scales, respectively. RESULTS: Probable PTSD participants exhibited steeper (more impulsive) delay discounting and endorsed more impulsive traits than participants in the trauma-exposed non-PTSD group. Moreover, the PTSD group reported significantly higher scores on both the AUDIT and CUDIT-R. Lastly, impulsive personality traits on the UPPS-P partially mediated the association between PTSD and both cannabis and alcohol use. CONCLUSIONS: These findings suggest that trauma-exposed individuals who exhibit elevated PTSD symptoms show heightened impulsivity. It also appears that lower levels of impulsivity may serve as a protective factor among trauma-exposed individuals resilient to the development of PTSD. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Associations Between Drinking and Cortical Thickness in Younger Adult Drinkers: Findings From the Human Connectome Project.

BACKGROUND: Previous neuroimaging studies examining relations between alcohol misuse and cortical thickness have revealed that increased drinking quantity and alcohol-related problems are associated with thinner cortex. Although conflicting regional effects are often observed, associations are generally localized to frontal regions (e.g., dorsolateral prefrontal cortex [DLPFC], inferior frontal gyrus [IFG], and anterior cingulate cortex). Inconsistent findings may be attributed to methodological differences, modest sample sizes, and limited consideration of sex differences. METHODS: This study examined neuroanatomical correlates of drinking quantity and heavy episodic drinking in a large sample of younger adults (N = 706; Mage  = 28.8; 51% female) using magnetic resonance imaging data from the Human Connectome Project. Exploratory analyses examined neuroanatomical correlates of executive function (flanker task) and working memory (list sorting). RESULTS: Hierarchical linear regression models (controlling for age, sex, education, income, smoking, drug use, twin status, and intracranial volume) revealed significant inverse associations between drinks in past week and frequency of heavy drinking and cortical thickness in a majority of regions examined. The largest effect sizes were found for frontal regions (DLPFC, IFG, and the precentral gyrus). Follow-up regression models revealed that the left DLPFC was uniquely associated with both drinking variables. Sex differences were also observed, with significant effects largely specific to men. CONCLUSIONS: This study adds to the understanding of brain correlates of alcohol use in a large, gender-balanced sample of younger adults. Although the cross-sectional methodology precludes causal inferences, these findings provide a foundation for rigorous hypothesis testing in future longitudinal investigations.