Associations between polygenic risk for tobacco and alcohol use and liability to tobacco and alcohol use, and psychiatric disorders in an independent sample of 13,999 Australian adults.

•Australian adults with high polygenic risk for starting regular smoking tended to be more susceptible to consuming more alcohol, developing nicotine dependence as well as conduct disorder.•We detected a significant effect of the interaction between sex and PRSs on the variation of alcohol consumption.•Polygenic risk scores (PRSs) for weekly consumption of alcohol explained up to 6.26 % of the variation of the same trait.•Polygenic risk scores may be used to identify high-risk individuals for targeted prevention.•Polygenic risk for starting regular smoking was positively associated with alcohol consumption, nicotine dependence and conduct disorder.