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.