The aim of this study was to investigate the overlap in polygenic risk factors between smoking behavior and alcohol- and cannabis use. Using polygenic risk scores derived from the GWA meta-analyses results of the TAG Consortium we predicted alcohol- and cannabis use in an independent sample from the Netherlands Twin Register. The risk scores for cigarettes per day explained .4–.5% of the variance in glasses alcohol per week and .6–.9% of the variance in cannabis initiation. The polygenic risk scores for age at onset of smoking predicted about 1.1–1.5% of the variance in age at regular alcohol use. The risk scores for smoking initiation and smoking cessation were not significantly associated with alcohol- and cannabis use.
