ANYDEP was defined as a binary variable where cases met lifetime criteria for DSM-IV dependence36 on alcohol, cannabis, cocaine, sedatives, stimulants and/or opioids (for prescription drugs, non-prescription use was specified) or any combination thereof. We did not include nicotine dependence as it was not assessed in earlier versions of the SSAGA, and was therefore missing for those who were only interviewed using older SSAGAs. Controls did not meet DSM-IV dependence criteria for alcohol or any drug listed above but were required to have consumed at least 1 drink of alcohol. Of the controls, 32.9% met lifetime criteria for DSM-IV alcohol or drug abuse (analyses excluding these individuals are described in the Discussion). For GWS SNPs, alcohol dependence and each individual DSM-IV drug dependence diagnosis was also examined against this uniform set of controls. As COGA was primarily ascertained for alcohol dependence, we created a variable for secondary analysis, drug_noalc, where individuals with alcohol dependence were excluded from the ANYDEP cases (and remained excluded from controls). Numbers of individuals for each phenotype are in Table 1.
