College students have an increased risk for cannabis use, trauma exposure, and posttraumatic stress disorder (PTSD). Cannabis use disorder (CUD) and PTSD comorbidity is high, and given the negative consequences of the comorbidity (e.g., poor academic outcomes), there is a need to understand comorbid CUD-PTSD etiology. Two primary etiologic models exist: self-medication (i.e., PTSD à CUD) and high-risk (i.e., CUD à PTSD) hypotheses. This study 1) examined the prevalence and predictors of cannabis use and interpersonal trauma (IPT) exposure; 2) investigated the relationship between cannabis use and IPT; and 3) examined cannabis use, IPT, and PTSD through mediational self-medication and high-risk hypotheses lenses in a large (n = 9,889) longitudinal study of college students. Aim 1 found the prevalence of lifetime problematic (i.e., use ≥ 6 times) and experimental (i.e., use 1-5 times) cannabis use was 28.3% and 17.4%, respectively. Aim 1 results also estimated that the prevalence of lifetime IPT exposure was 35.9%. Aim 2 results supported the self-medication hypothesis, but not the high-risk hypothesis. Overall model fit from Aim 3 was poor. Nonetheless, Aim 3 results did not support the self-medication or high-risk hypotheses. Given the poor model fit of Aim 3, results should be interpreted with caution. However, as a whole, these findings provide preliminary support for the self-medication hypothesis, indicating that those reporting IPT exposure and probable PTSD may be at risk for cannabis use. Implications of these findings, in light of study limitations, are discussed
