Selection of control families was based on availability of families with children between the ages of 8–18. Each control family was selected on basis of residence within a census track from which a high risk family had been selected with an attempt made to yoke each control family to a high risk family in the study. Random phone calls were made to homes within the census track to determine if the family had available children and were interested in participating in the study. Those expressing an interest were sent a letter of introduction. Parents were screened for absence of alcohol and drug dependence using the DIS, though other psychopathology was free to vary. 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 alcohol dependence. All control families had a low density of familial alcohol dependence. Most low-risk control families had an absence of alcohol or drug dependence among all first-degree relatives. However, three low-risk mothers were identified
