ABSTRACT
The first chapter of this book by Vujanovic and Back clearly outlines the public health relevance of co-occurring posttraumatic stress disorder (PTSD) and substance use disorders (SUD), including the challenges that clinicians and health workers face when addressing the treatment needs of this population. In order to best address these treatment challenges, we must understand the etiological and maintenance factors contributing to the onset of comorbid PTSD/SUD. This chapter aims to review the predominant etiological models for PTSD/SUD and is written with several key assumptions in mind. The first is that the proposed theoretical explanations for PTSD/SUD etiology are not mutually exclusive. Rather, we have the task of synthesizing the available data from a variety of methodological perspectives to inform a complex picture of the numerous and varied influences on PTSD/SUD development. This chapter will review evidence for explanatory models of PTSD/SUD, with the understanding that there is no single best model, but complementary explanations across multiple models. It may be the case that individuals experience risk from each of the described sources, and it may be that different models are more relevant for certain individuals. The second assumption is that not all explanations of PTSD/SUD comorbidity assume causal associations between these disorders. Our framework for understanding PTSD/SUD etiology must accommodate the evidence that a proportion of the covariation between these disorders is explained by common factors, as described below. By increasing our awareness and understanding of the heterogeneity of etiologies underlying PTSD/SUD, we will be better positioned to identify multiple prevention and intervention targets at different points over the course of development.
