Two sets of case-control samples (AA: 199 controls and 455 cases; EA: 483 controls and 336 cases) were recruited. All AA and EA cases, 151 AA controls, and 126 EA controls were assessed with the SSADDA instrument (26). 48 AA controls and 357 EA controls were evaluated using the Structured Clinical Interview for DSM-III-R (SCID-III-R) (American Psychiatric Association, 1987) or DSM-IV (SCID-IV) (American Psychiatric Association, 1994), as described previously (28). Cases were diagnosed with alcohol dependence (AD), CD, and/or OD using the SSADDA instrument. Control subjects were screened to exclude those with major Axis I mental disorders, including alcohol or drug dependence, mood disorders, major anxiety disorders, and psychotic disorders. In general, the control subjects were younger and more likely to be female than the case subjects. The ethnicity of case and control subjects was self-identified. The genetic background of a majority of case and control subjects was also analyzed using a set of ancestry-informative markers (AIMs) (see below).
