PTSD contributes to teen and young adult cannabis use disorders

Previous studies involving adults suggest that Post Traumatic Stress Disorder (PTSD) increases the prevalence of cannabis use disorders (CUD) (cannabis dependence and cannabis abuse). However, little work with PTSD and CUD has been conducted involving adolescents, despite the fact that CUD typically have their onset during adolescence. This study addresses the effect of PTSD on CUD among teenagers transitioning to young adulthood.

The subjects in this ongoing study were the offspring of adult men with a lifetime history of a substance use disorder (SUD) (SUD+probands, N=343) vs those with no lifetime history of a SUD (SUD-probands, N=350). The participants were initially recruited when the index sons of these fathers were 10-12 years of age, and subsequent assessments were conducted at age 12-14, 16, 19, 22, and 25. Other variables examined were an index of behavioral undercontrol associated with future risk for developing SUD, known as the Transmissible Liability Index, or TLI, and affiliation with deviant peers. Multivariate logistic regression and path analyses were conducted.

Of these 693 subjects, 31 subjects were diagnosed with PTSD, and 161 were diagnosed with a CUD. The CUD subjects included 136 male participants and 25 female participants, including 103 (64%) Caucasian participants and 58 (36%) participants of other races. Logistic regression demonstrated that the development of a CUD was associated with deviance of peers (Wald=63.4, p=0.000), the TLI (Wald=28.8, p=0.000), African American race (Wald=14.2, p=0.000), PTSD (Wald=12.7, p=0.000), male gender (Wald=12.0, p=0.001), household SES (Wald=9.2, p=0.002), and being an offspring of a SUD+proband (Wald=6.9, p=0.009). Path analyses demonstrated that PTSD is directly associated with the presence of a CUD and with peer deviance, that higher peer deviance is associated with the presence of a CUD, and that PTSD mediated the association between peer deviance and CUD.

These findings suggest that PTSD contributes to the etiology of CUD among teenagers making the transition to young adulthood beyond the effects of deviant peers, the TLI (Transmissible Liability Index, a measure of risk for SUD), and demographic factors.