Do Cannabis Use Motives Mediate the Relationship between PTSD Symptoms and Cannabis Craving to Trauma Cues?

Cannabis use is common in individuals with posttraumatic stress disorder (PTSD). The PTSD-cannabis relationship is important as cannabis use can worsen PTSD outcomes. Cannabis use motives are a useful construct for understanding the PTSD-cannabis relationship. Frequent pairing of a trauma cue with substance use to cope can lead to conditioned substance craving. The extant research has not yet examined potential mechanisms to explain this effect. We recruited 51 cannabis users with a trauma history for a cannabis cue-reactivity study to examine coping motives as a potential mediator of the hypothesized relationship between PTSD symptoms and cannabis craving to trauma cues. Participants first completed a validated cannabis use motives measure. They were then exposed to a personalized audio and visual cue based on their trauma experience and reported on their cannabis craving immediately following using a standardized measure. Coping motives were contrasted with enhancement motives as the mediator. Results supported our first hypothesis: PTSD symptoms were associated with increased cannabis craving following personal trauma cue exposure. However, our second hypothesis of an indirect effect through coping motives was not supported. We did find an independent main effect of coping motives on cannabis craving triggered by trauma cue exposure. The lack of an interaction between PTSD symptoms and coping motives on trauma-cue induced craving is potentially due to other factors we did not examine that help strengthen the relationship (e.g., sleep). These findings have important clinical implications for targeting both PTSD symptoms and coping motives to prevent the development of conditioned cannabis craving to trauma reminders.