Parallel process modeling of posttraumatic stress disorder symptoms and alcohol use severity in returning veterans.

Posttraumatic stress disorder (PTSD) is associated with higher levels of alcohol use among returning veterans. Persistent PTSD symptoms can predict alcohol use over the span of hours, days, weeks, and months; however, knowledge of the strength of these associations beyond 1 year remains limited. In this study, we examined the 6-year course of co-occurring PTSD and alcohol use to explicate the directional and possible enduring effects of PTSD on alcohol use severity over time. Our study included 1,649 returning veterans ( age = 37.49; = 9.88) who completed 4 waves of data collection between 2010 and 2016. We used parallel process modeling to evaluate temporal associations between PTSD symptoms and alcohol use severity across 4 (T1-T4) waves of data collection. PTSD and alcohol use both decreased significantly between T1 and T4 and in tandem with one another. That is, decreases in one were associated with decreases in the other. Further, individuals with higher levels of PTSD symptom severity at T1 reported accelerated rates of change regarding PTSD symptoms and alcohol use over time. Conversely, baseline alcohol use severity did not predict the rate of change in PTSD symptom severity. Our findings provide evidence of a prospective association between PTSD symptoms and alcohol use and highlight the potential for reciprocal associations between them over the span of years. Importantly, our demonstration of the natural course of co-occurring PTSD symptoms and alcohol use suggests further trauma-focused and combined intervention strategies are needed to disrupt this enduring and reciprocal pattern among returning veterans. (PsycInfo Database Record (c) 2020 APA, all rights reserved).