The overall predictive power of the PGS alone was in the range of 1.1–3.7%. Only the PGS for externalizing problems, problematic alcohol use, and cigarettes per day were consistently associated with SUD outcomes. The PGS for externalizing problems was associated with drug dependence and nicotine dependence, the PGS for problematic alcohol use PGS was associated with alcohol dependence, and both were associated with any substance dependence. The PGS for cigarettes per day was only associated with nicotine dependence. Overall, these results support prior evidence that genetic risk for SUDs consists of a both shared and substance-specific variance [31, 41, 47].
