Background: College students are at high risk for cannabis use, interpersonal trauma (IPT) exposure, and posttraumatic stress disorder (PTSD). Two phenotypic etiologic models posited to explain associations between cannabis use and trauma-related phenotypes are the self-medication (trauma/PTSD cannabis use) and high-risk (cannabis use trauma/PTSD) hypotheses. The primary objective of this study was to investigate direct and indirect associations among cannabis use, IPT exposure, and PTSD above and beyond established covariates.Methods: The current study used data from the first assessment (i.e., baseline survey at year 1 Fall) and two follow-up assessments (i.e., year 1 Spring and year 2 Spring) from an ongoing longitudinal study on college behavioral health. Participants were four cohorts of college students (n = 9,889) who completed measures of demographics, substance use, IPT, and PTSD. Indirect effects of IPT on cannabis through PTSD (i.e., self-medication) and cannabis on PTSD through IPT (i.e., high-risk), including tests of covariate effects (e.g., sex, age, race, cohort, alcohol, nicotine) were simultaneously estimated using a longitudinal mediation modeling framework.Results: Results suggest that more IPT exposure increases risk for PTSD and subsequent non-experimental (use 6+ times) cannabis use, and that experimental (use 1 – 5 times) and non-experimental cannabis use increases risk for IPT exposure and subsequent PTSD.Conclusions: Both the self-medication and high-risk hypotheses were supported. Findings support a bidirectional causal relationship between cannabis use and trauma-related phenotypes. Additionally, results highlight areas for colleges to intervene among students to help reduce cannabis use and create a safer environment.
A Systematic Review of the Self‐Medication Hypothesis in the Context of Posttraumatic Stress Disorder and Comorbid Problematic Alcohol Use