Characterizing Associations Between Trauma and Substance Use and Related Problems Among Samples with Differing Clinical Presentation & Severity

Abstract

Posttraumatic stress disorder (PTSD) and substance use disorder (SUD) frequently co-occur. Comorbid PTSD+SUD confers heightened risk of other mental health concerns, suicidality, mortality, and functional impairment. Current treatments for comorbid PTSD+SUD show inconsistent results, highlighting the need for a more comprehensive understanding of the associations between PTSD and SUD symptoms. The current dissertation aimed to characterize the associations between PTSD and SUD using structural equation modelling among three different samples with differing clinical severity and presentation: (1) concurrent disorders sample with a high prevalence of PTSD; (2) an in-patient sample seeking treatment for PTSD; and (3) a subclinical sample of healthcare workers and public safety personnel. Data were extracted from multiple clinical databases across different studies to evaluate the associations between PTSD symptoms and alcohol/cannabis/substance use-related problems. Furthermore, the role of underlying mechanisms such as dissociation and emotion dysregulation, which are associated with both PTSD and SUD, were analyzed. All analyses used a structural equation modelling framework to represent the complex clinical presentation of comorbid PTSD+SUD analytically. A relatively consistent pattern of results was observed across the three samples. Global PTSD symptoms were significantly associated with cannabis-related problems, alcohol-related problems, and other illicit substance-related problems. Among PTSD symptoms, the reactivity symptom cluster (characterized by symptoms of hypervigilance, irritability, reckless behaviour, problems with concentration and sleep disturbances) was significantly associated with alcohol/cannabis/substance-related v problems across among the three samples. Furthermore, underlying mechanisms such as dissociation and emotion dysregulation significantly mediated the relations between PTSD symptoms and alcohol/cannabis/substance-related problems. Overall, the current results contribute to the limited literature examining the associations between PTSD and SUD symptoms. Lastly, the current results have important clinical implications for identifying efficacious treatment targets for comorbid PTSD+SUD.