Associations between substance use, post-traumatic stress disorder and the perpetration of violence: A longitudinal investigation

Aim: Substance use disorder (SUD) and post-traumatic stress disorder (PTSD) commonly co-occur. This is of significant concern, given the increased risk for violence perpetration among individuals with this comorbidity. Limited research, however, has examined relationships between SUD, PTSD and violence among individuals longitudinally. Such an investigation is warranted given that substance use and PTSD symptoms can fluctuate over time. This study therefore aims to examine how changes in substance use and PTSD symptom severity are associated with the perpetration of violent crime over time among individuals with comorbid SUD and PTSD. Method: One-hundred and two men and women who met criteria for SUD and PTSD were interviewed four times over a 9-month period. These interviews included measures of past-month violent crime perpetration, substance use and dependence, PTSD symptom severity, and depression and state anxiety symptoms. Generalised estimating equations (GEE) modelled associations between substance use, PTSD and violence. Results: Increased substance use, more severe substance dependence and more severe PTSD symptomology were consistently associated with violent crime over time. Multivariate GEE analyses, however, revealed that the PTSD hyperarousal symptoms, specifically, were independently associated with violence over time. Conclusions: This longitudinal study found that PTSD hyperarousal symptoms were consistently associated with the perpetration of violent crime, further highlighting the potentiating role of PTSD hyperarousal in relation to violence among individuals with SUD. These findings indicate that interventions addressing hyperarousal symptoms have the potential to reduce the susceptibility for violence among individuals with this common comorbidity. (C) 2014 Elsevier Ltd. All rights reserved.