Gender differences in genetic and environmental influences on gambling: results from a sample of twins from the National Longitudinal Study of Adolescent Health

Aims To examine the extent to which genetic factors and shared and non-shared environmental factors are implicated in the development of gambling behaviors and to examine whether there are gender differences in the genetic and environmental contributors to gambling behaviors. Design A genetically informative analysis was performed by using DeFries-Fulker (DF) analysis. Setting Analysis of secondary data drawn from the National Longitudinal Study of Adolescent Health (Add Health). Participants A total of 324 monozygotic (MZ) twins and 278 same-sex dizygotic (DZ) twins were included in the analysis. Of these twins, there were 150 male MZ twins, 144 male DZ twins, 174 female MZ twins and 134 female DZ twins. Measurements Gambling behavior was measured through eight self-reported questions that tapped a range of items designed to measure problems related to gambling. Self-reported measures of self-control and delinquent involvement were also included to examine the degree to which these factors covaried with gambling behavior. Findings The results of the DF analysis indicated that when male and female twin pairs were analyzed simultaneously, genetic factors explained approximately 70% of the variance in gambling and non-shared environmental factors explained the remaining variance. When gender-specific models were calculated, substantial gender differences emerged. For males, genetic factors explained approximately 85% of the variance in gambling, with the non-shared environment accounting for the remaining variance. For females, genetic factors explained none of the variance in gambling behaviors, while the shared environment explained 45% of the variance and the non-shared environment explained 55% of the variance. Conclusions Analysis of twins from the Add Health data suggests that there are significant gender differences in the genetic and environmental underpinnings to gambling behaviors.