Genetic influences on the interplay between obsessive‐compulsive behavior symptoms and cannabis use during adolescence

Introduction There are overlapping biological origins and behaviors associated with obsessive‐compulsive symptoms (OCS) and cannabis use. There is also evidence that OCS and cannabis use are associated over time. Thus, we investigated polygenic predisposition for OCS as predictive of OCS and cannabis use from age 17 to 19. We hypothesized that greater genetic risk for OCS would predict both OCS and cannabis use. Methods The current study used participants from the Project Alliance 1 study, a US‐based sample, for whom genomic, OCS, and cannabis use data were available (n = 547). Polygenic risk scores (PRS) were formed via a meta‐genome‐wide association study on OCS and examined as a predictor of OCS and cannabis use at age 17 and 19. The sample was diverse (52.4% male; 45% European American, 30% African American, 14% multiracial, 5% Hispanic/Latino, 4% Asian American, and 2% other groups). Sensitivity analysis was performed by gender for European American and African American subsamples. Results Across the whole sample, the greater polygenic risk for OCS was negatively associated with cannabis use at age 17 and positively associated with OCS at 19. Cannabis use at age 17 was positively associated with OCS at age 19. The association between polygenic risk for OCS and cannabis use at age 17 was replicated in European American males, whereas the association between cannabis use at age 17 and OCS at age 19 was replicated in African American males. Conclusions Cannabis use may exacerbate OCS through adolescence, and genetic predisposition for OCS may be associated with lower cannabis use in efforts to avoid exacerbation of OCS.