Chunk #5 — Basic methodology of genetic epidemiology: an overview of twin studies — Principle 1: Genetic influences change in importance across adolescence
Alcohol use is a common form of risky behavior in adolescence, and alcohol use is a developmental phenomenon. Cross-sectional and longitudinal studies of alcohol use reveal age-related patterns. Although some children begin drinking in earlier ages, alcohol use typically begins in adolescence (Faden, 2006). Between ages 12 and 21, rates of alcohol use and heavy episodic drinking increase sharply. National survey data indicate that the percentage of American youth who have ever drunk at least one whole drink rises steeply across adolescence, leveling off at about age 21 (SAMHSA, 2007). Recent national data further show that all levels of past-month alcohol use increase steadily across adolescent years, including any alcohol use, binge use, and heavy use (SAMHSA, 2014). Similarly, data from the Monitoring the Future study, a nationally representative sample of 8th, 10th, and 12th graders, demonstrate that the prevalence of binge drinking (having 5+ drinks at least once in the past two weeks) increases substantially from 8th grade to 12th grade (Johnston et al., 2016). Notably, frequency of binge drinking also increases across this developmental period. Data from the
