Chunk #8 — Basic methodology of genetic epidemiology: an overview of twin studies — Principle 1: Genetic influences change in importance across adolescence
genetic factors assume increasing importance; however, alcohol use early in adolescence is influenced largely by family, school, and neighborhood factors (Rose et al., 2001b; Rose et al., 2003). A very similar pattern of results for alcohol use was obtained by a life-history method in male twin pairs from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders (Kendler et al., 2008b). At age 14, all twin resemblance resulted from shared environmental factors. From ages 14 to 23, shared environment became progressively less important and genetic factors more important.
