A Population-Based Twin Study of Alcoholism in Women

Objective.—To clarify the role of genetic factors in the etiology of alcoholism in women. Design and Setting.—Personal structured psychiatric interviews conducted by researchers “blinded” to the status of the co-twin in an epidemiologic sample of 1030 female-female twin pairs of known zygosity from the population-based Virginia Twin Registry. Measures.—Three definitions of lifetime prevalence of alcoholism based on Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised criteria: (1) alcoholism with tolerance or dependence; (2) alcoholism with or without tolerance-dependence; and (3) alcoholism with or without tolerance-dependence or problem drinking. Results.—Using narrow, intermediate, or broad definitions, the probandwise concordance for alcoholism was consistently higher in monozygotic than in dizygotic twin pairs. Multifactorial threshold models suggested that the heritability of liability to alcoholism in women is in the range of 50% to 60%. Conclusions.—The results support the hypothesis that genetic factors play a major role in the etiology of alcoholism in women. Women should be well represented in the efforts currently under way to elucidate the molecular basis of the genetic susceptibility to alcoholism.