The polygenic risk score based on age at onset of smoking was significantly associated with age at which regular drinking started. This risk score was not associated with any of the other alcohol or cannabis phenotypes (Table 3A). The polygenic risk scores ever and former smoking did not significantly predict alcohol- or cannabis use (Table 3B en 3C). The risk scores based on CPD were significantly associated with the number of glasses alcohol per week and cannabis initiation, but not with age at regular drinking or age at first cannabis (Table 3D).
