Our finding of a moderating effect of religiosity on the etiology of adolescent alcohol problem scores is consistent with other studies demonstrating a moderating effect in adolescence (Cleveland and Wiebe 2003; Dick et al. 2007; Koopmans et al. 1999; Penninkilampi-Kerola et al. 2005). The lack of a significant moderating effect on the heritability in young adulthood is in contrast to the previous limited findings in adulthood, which showed a significant moderating effect of both marital status (Heath et al. 1989) and co-twin dependence (Penninkilampi-Kerola et al. 2005). However, both of these studies focused on alcohol use, rather than the more extreme alcohol problems, as was assessed in the current study. Furthermore, our results showed that religiosity significantly decreases longitudinally from adolescence to young adulthood, providing direct evidence of a decline in social control.
