Cannabis use among military veterans: A great deal to gain or lose?

Policy changes have resulted in dramatic increases in access to cannabis for medical purposes. Veterans are disproportionately affected by conditions for which medical cannabis is often pursued, making an evidence-based perspective on risks versus benefits of high priority. The current review sought to examine the state of the evidence on the correlates and consequences of cannabis use among veterans. Using a comprehensive search strategy, 501 articles were identified and 86 studies met criteria for inclusion. The literature was predominated by cross-sectional studies (67%) of male veterans (71.4%-100% male) from the United States (93.0%). Three overarching themes emerged, comprising cannabis associations with other substance use, mental health, and physical health outcomes. The balance of the evidence associated cannabis use with negative health outcomes, with consistent positive associations with other substance use, psychiatric disorders, and self-harm/suicidality. Few studies examined the therapeutic effects of cannabis, thus limiting the potential to evaluate evidence of efficacy. Priority areas for future research are studies using designs that can examine the directionality of links between cannabis and health in veterans more conclusively, and studies directly examining therapeutic efficacy of cannabis-based therapies in veterans. Methodologically rigorous design will be essential to inform clinical recommendations and practices guidelines in an era of burgeoning access to cannabis.