Analyses were performed contrasting high and low risk offspring for four different outcomes: alcohol abuse, drug abuse, alcohol dependence and drug dependence adjusting for the participant’s age at last visit through use of survival analyses. For participants who received a positive substance use disorder diagnosis before the age of 18, the diagnosis was made using information from the K-SADS instrument, and therefore, was determined by DSM-III criteria. If a positive diagnosis occurred after the age of 19, the diagnosis was obtained from administration of the CIDI interview and was based on DSM-IV criteria. Offspring from multiplex AD families had a significantly earlier onset for Alcohol Abuse and Alcohol Dependence (Figure 1) and Drug Abuse and Drug Dependence (Figure 2). Comparison of Figures 1 and 2 shows a steeper slope for drug abuse/dependence than alcohol abuse/dependence for high risk offspring, suggesting that drug abuse/dependence occurs earlier than does alcohol abuse/dependence.
