The moderating effect of religiosity on the genetic variance of problem alcohol use.
BACKGROUND
Previous studies have demonstrated that the heritability of alcohol-related phenotypes depends upon the social background in which it is measured (e.g., urbanicity, marital status, and religiosity). The aim of the current study was to identify whether religiosity moderated the genetic variance of problem alcohol use in men and women at two time points: adolescence and early adulthood.


METHOD
Participants were 312 male MZ pairs, 379 female MZ pairs, 231 male DZ pairs, 235 female DZ pairs, and 275 opposite sex DZ pairs participating in the University of Colorado Center on Antisocial Drug Dependence. Religiosity was measured using the Value on Religion Scale (Jessor and Jessor, 1977), and problem alcohol use was measured using the Composite International Diagnostic Interview-Substance Abuse Module (Cottler et al., 1989). Data were analyzed using a model-fitting approach to the twin data.


RESULTS
In adolescence, genetic variance of problem alcohol use decreased significantly with increasing levels of religiosity in both men and women, whereas in early adulthood, religiosity did not moderate the genetic variance of problem alcohol use in either men or women.


CONCLUSION
Religiosity appears to moderate the genetic effects on problem alcohol use during adolescence, but not during early adulthood. The reduced genetic variance for problem alcohol use in adolescence may be the consequence of greater social control in adolescence than in young adulthood.