Family history models of alcoholism: age of onset, consequences and dependence.

The association of a family history of alcoholism to susceptibility to alcoholism has been well documented over the past 3 decades. The classification of a family history of alcoholism commonly involves the division of subjects into family history positive and negative groupings. However, diverse definitions are used to define positive family histories. These diverse definitions of family alcoholism impede the comparison of results from different studies. The present study evaluates several classification schemes and compares them with a new method for the analysis of family patterns of alcoholism (FPA). A sample of 220 male alcoholic veteran inpatients were assessed for age of onset of alcoholism, consequences of drinking and the severity of their dependence. Multiple regression equations were estimated for several dichotomous family history models and each model was evaluated against a comparable FPA model that included the same family members. Comparisons of the classification models with the equivalent FPA analysis model facilitated comparisons of the contribution of each family history designation to changes in amount of explained variance. In all instances, the FPA analyses explained more variance than did the comparable dichotomous family history models. In addition, the FPA analyses reveal the relative explanatory power of each family member and indicate that maternal relatives often have a more important contribution than has been indicated previously.