FAMILIAL RESEMBLANCES IN ALCOHOL-USE - GENETIC OR CULTURAL TRANSMISSION

Objective: Resemblances between parents and children for alcohol use c an be due both to cultural transmission and genetic inheritance. We ex amined the genetic and environmental determinants of the familial rese mblances in alcohol use. Method: With a parent-twin design a distincti on was made between the contribution of genetic effects, the environme ntal influences shared by siblings and the effects of cultural transmi ssion from parents to offspring. By questionnaire, data on whether sub jects had ever used alcohol were obtained from 403 Dutch families with a twin aged 15-16 years old and from 805 families with a twin aged 17 years and older. Results: For 15-16 year olds, the resemblance betwee n parents and offspring could be explained either by genetic inheritan ce or cultural transmission. Shared environment explained between 58% and 88% of the individual differences in adolescent alcohol use. For t wins aged 17 years and older, 43% of the individual differences in alc ohol use could be attributed to genetic factors and 37% to shared envi ronment. There was no evidence for cultural transmission in this age g roup. Conclusions: For adolescents aged 17 years and older, parental a lcohol use did not create an environment that stimulated alcohol use i n children. The resemblance for alcohol use between parents and their children aged 17 years and older could be explained by their genetic r elatedness. For 15-16 year old adolescents, shared environmental influ ences were more important than for older adolescents. Only 10% of this shared environmental variance might be influenced by parental alcohol use due to cultural transmission.