The finding that AUDs in both parents had a stronger association with earlier than later cannabis use is consistent with a recent study which showed that parental alcohol problems were associated with increased opportunity to use cannabis and with increased risk of initiating use, given the opportunity (29). Recent evidence showed that the age at initiation of cannabis use was more strongly influenced by shared environment than were ages at initiation of tobacco and alcohol, suggesting that this might be due to the illegality of cannabis (in most states), making it harder to procure (14). Parents with AUDs may provide less monitoring of child behavior than parents without AUDs (18, 19), increasing the likelihood that offspring will have access to cannabis via deviant peers. Parental AUDs may also represent a general risk for psychosocial and substance use problems via increased genetic risk for conduct problems and other substance use (58).
