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 as having past alcohol abuse or dependence in late adolescence or early adulthood but had been free of any substance use disorder for numerous years (i.e. ≥ 6) before study entry. In addition, one father who married into the target pedigree family had drug dependence.
