The association between recreational cannabis use and posttraumatic stress disorder: A systematic review and methodological critique of the literature.

Background: Given recent changes in the legal status of cannabis, the risks and benefits associated with its use have become an important public health topic. A growing body of research has demonstrated that posttraumatic stress disorder (PTSD) and recreational cannabis use (RCU) frequently co-occur, yet findings are inconsistent (e.g., direction of effect) and methodological variability makes comparison across studies difficult. Methods: We conducted a comprehensive systematic review of all studies (N = 45) published before May 2020 regarding etiologic models of co-occurring RCU and PTSD, as well as provided a methodological critique to inform suggestions for future research initiatives. Results: Findings indicate that a majority of studies (n = 37) demonstrated a significant association between RCU and PTSD. Findings provide evidence for the self-medication and high-risk models posited to explain co-occurring RCU and PTSD despite variability in assessment of RCU, which includes commonly used non-standardized self-report questions. Conclusion: The association between RCU and PTSD is likely bidirectional. Results inform clinicians and researchers working in the mental health and cannabis use fields how the variability in findings on the association between RCU and PTSD may be attributable, in part, to methodological issues that permeate the extant literature pertaining to RCU and PTSD.