Longitudinal associations of cannabis, depression, and anxiety in heterosexual and LGB adolescents

Cannabis use is linked to symptoms of depression and anxiety, particularly among sexual minorities.This study examines the relationships between cannabis, and depression and anxiety symptoms at 13,15, and 17 years using cross-lagged models in a predominantly White (n= 1,430; 92%) subsample of1,548 participants from the Quebec Longitudinal study of Child Development. Multigroup analyseswere conducted to examine the models according to sexual orientation. Demographic covariates wereincluded as control variables, as well as alcohol, cigarette, and other drug use to examine cannabis spec-ificity. The full sample revealed small bidirectional associations, which remained significant once con-trol variables were included in the model: cannabis at 13 and 15 years predicted anxiety symptoms at 15and 17 years respectively, and depression symptoms at 15 years predicted cannabis at 17 years. The ini-tial association between cannabis at 13 years and depression symptoms at 15 years was accounted forby other drug use at 13 years. Substantial differences were found between heterosexual participants andsexual minorities: LGB participants presented a substantially larger positive association between depres-sion symptoms at 15 years and cannabis at 17 years, as well as a negative association between anxietysymptoms at 15 years and cannabis at 17 years. Both of these relationships remained significant whenaccounting for control variables. These results suggest that the relationships between cannabis, anddepression and anxiety symptoms are bidirectional across adolescence, albeit small. Sexual minoritiespresent particularly large associations that may represent self-medication efforts for depressive symp-toms between 15 and 17 years