Subjects were interviewed using the SSADDA for psychiatric diagnosis as described previously (23, 26, 27). The diagnosis of AD was based on application to the SSADDA data set of a computer algorithm using DSM-IV diagnostic criteria. 355 subjects were affected with AD, and a further 184 met criteria for alcohol abuse. For the purpose of these analyses, we considered subjects who met the diagnosis of alcohol abuse to be diagnostically unknown; this was intended as a conservative way to treat subjects who could not be definitively characterized as affected or unaffected.
