Each control family was initially recruited by place of residence and whether children between the ages of 8–18 lived within the home. Each control family was selected for their residence within a census track from which a high-risk family had been selected. This provided a yoked control for neighborhood characteristics. Families qualifying by these characteristics were further screened to determine the psychopathology within the family. Mothers were designated as the "index" case and screened for absence of alcohol and drug dependence using the DIS, though other psychopathology was free to vary with the exception of schizophrenia and bipolar disorder. Diagnostic data were also collected for all first degree relatives using either an in-person DIS interview or by obtaining multiple family history reports to ensure an absence of a family history of AD. Accordingly, all control families had a low density of familial AD.
