Objective: This study examines the familial transmission of alcohol abuse and dependence to adolescents.
Method: Male adolescents recruited from a treatment program for substance problems, matched controls, and all available biological parents and siblings were assessed with a structured psychiatric interview assessing Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, based diagnoses of alcohol abuse and alcohol dependence. A total of 2,612 individuals from 911 families were interviewed. Structural equation modeling estimated tetrachoric correlations among family members, the proportion of variance in abuse and dependence attributable to parent-offspring transmission, and the effects of assortative mating and horizontal transmission among siblings.
Results: Tetrachoric correlations among siblings and parent-offspring ranged from .19 to .34 for abuse and dependence. Mother-father correlations were .14 and .37 for abuse and dependence, respectively. Modeling of familial transmission showed that 33% of the variance in abuse and 56% of the variance in dependence was accounted for by factors transmitted from parents. The effects of assortative mating could not be dropped from the abuse model without significant loss of model fit but could be dropped from the dependence model. Horizontal transmission among siblings could be dropped from both models without significant loss of fit.
Conclusions: These results suggest that aggregation of alcohol abuse and alcohol dependence in families of male probands is significantly influenced by parental transmission of risk but is not reliably influenced by horizontal sibling effects such as sibling interactions or cohort effects. Spousal resemblance was found to be an important source of familial aggregation for alcohol abuse but not alcohol dependence.