Reduced access to rewarding activities explained the link between PTSD symptoms and cannabis misuse in college students

Environmental suppression (ES) on the Reward Probability Index fully mediated the relationship between PTS symptoms (PCL-5) and cannabis misuse (CUDIT-R). Reward probability (the ability to experience pleasure) did not mediate this relationship. This suggests that restricted access to non-substance rewards, rather than anhedonia, drives the PTS-cannabis connection.

Cross-sectional design with 404 undergraduate students who completed the Reward Probability Index, PCL-5, and CUDIT-R. Parallel mediation path analysis testing two RPI subscales as mediators.

Distinguishing between "cannot feel pleasure" (reward probability) and "environment limits rewarding activities" (environmental suppression) has direct treatment implications. If restricted reward access drives cannabis use in trauma-exposed individuals, increasing access to positive activities may reduce substance use.

If limited access to rewarding experiences drives cannabis use after trauma, behavioral activation interventions that expand positive activities could address both PTSD and cannabis misuse simultaneously, rather than treating them as separate conditions.

Cross-sectional design cannot confirm causal mediation. College student sample limits generalizability to other trauma-exposed populations. Self-reported measures. Single time point cannot capture dynamic processes.