Not how often but when: Self-efficacy to control cannabis use and PTSS.

Objective: Cannabis use is prevalent with trauma survivors. Yet, the effects of cannabis use on posttraumatic stress symptoms (PTSS) have been equivocal with some studies showing a positive association and some showing a negative association. Integrating the self-medication hypothesis and social cognitive theory (SCT), the present study aimed to elucidate differential outcomes by considering frequency of cannabis use and self-efficacy to control cannabis use in different contexts (i.