Genetic and environmental influences on alcohol use: DF analysis of NLSY kinship data

Research designs to study alcohol use and abuse have included twin, adoptio n and family history/high risk studies. Results have consistently implied a genetic factor in the aetiology of alcohol abuse. However, less research h as been conducted in search of environmental factors. This study uses kinsh ip structure in a large national dataset (the National :Longitudinal Survey of Youth) to estimate (using DeFries-Fulker analysis) the extent of the sh ared genetic, non-shared genetic, shared environmental and non-shared envir onmental influences on alcohol use. The NLSY kinship sample contained 3890 pairs of cousins, half-siblings, full-siblings and twins between the ages o f 14 and 21 in the initial year of the survey (1979). Estimates of heritabi lity (h(2)) and shared environment (c(2)) were small to moderate for the en tire dataset for both light drinking and heavy drinking behaviour, with h(2 ) estimates slightly higher in each case. Non-shared genetic measures of se lf-esteem and locus of control accounted for a significant portion of the r emaining variance in heavy drinking behaviour. Race and gender patterns sho wed c(2) and h(2) estimates that were also small to moderate for both light and heavy drinking behaviour. Significant non-shared effects were found fo r the White group for heavy drinking behaviour, and for male pairs for both heavy and light drinking behaviour. Additionally, implications and future directions are discussed.