A common psychiatric assessment was performed across all three studies based on the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) (Bucholz et al., 1994), allowing for pooling of phenotypic data. In all studies, cases were identified as having a lifetime history of AD according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Controls were individuals who had been exposed to alcohol (and possibly to other drugs) but had not developed alcohol or drug abuse and/or dependence in their lifetime. Controls were also screened to exclude individuals with major Axis I disorders, such as schizophrenia, mood disorders, and anxiety disorders.
