A Prospective Study of the Effects of Age of Initiation of Alcohol and Drug Use on Young Adult Substance Dependence * (Report‪)‬

THE AGE AT WHICH AN ADOLESCENT begins using alcohol, commonly operationalized as the age at which they take their first drink, is thought to be an important predictor of later alcohol-use behaviors. Empirical research has consistently associated early onset of alcohol use with heightened risk for alcohol problems and dependence (DeWit et al., 2000; Grant and Dawson, 1997, 1998; Hawkins et al., 1997; McGue et al., 2001, 2006). Prospective studies have shown that adolescents who have their first drink of alcohol at younger ages tend to report more alcohol-related problems later, in adolescence (e.g., Hawkins et al., 1997) and adulthood (Chou and Pickering, 1992; Pitkanen et al., 2005; Warner and White, 2003). Retrospective studies have shown a similar association between early drinking and alcohol dependence (e.g., McGue et al., 2001; Prescott and Kendler, 1999). For example, Grant and Dawson (1997) used retrospective data from nearly 27,000 adults from the National Longitudinal Alcohol Epidemiological Survey to show that the risk for alcohol dependence decreased by 14% for every year that drinking was delayed, even controlling for gender and familial alcohol problems. This research suggests that delaying the onset of alcohol use reduces the risk for alcohol-use disorders. Yet early-adolescent alcohol use has been theorized to be part of a larger developmental trajectory that leads to later problems with alcohol and drugs and antisocial behaviors (e.g., Flory et al., 2004; Krueger et al., 2002; McGue et al., 2001). Prospective studies, including many from the same sample as the current study, have shown that the childhood precursors of both adolescent alcohol use and alcohol dependence include impulsive, disinhibited temperaments (Chassin et al., 1999; Sher and Trull, 1994): problem behaviors (Fergusson et al., 1996); parental alcoholism and antisociality (Chassin et al., 1999); and family environments, including poor parenting (Baumrind, 1991; Chassin et al., 1996) and family conflict (Wills et al., 2001; Zhou et al., 2006). Moreover, many of these same risk factors, such as family history of alcoholism (Dawson, 2000; Hawkins et al., 1997) and impulsive and externalizing behaviors among boys and girls (Flory et al., 2004, McGue et al., 2001) or among girls only (Pitkanen et al., 2005), have been linked to early onset of alcohol use. Multiple developmental theories have posited that these behavioral and environmental factors interact to set an adolescent on a developmental trajectory that leads to early-onset alcohol use in adolescence and alcohol dependence by young adulthood (e.g., Sher, 1991: Tarter et al., 1999). These theories and empirical research suggest that early onset of alcohol use occurs as a result of a complex behavioral and environmental interaction, and this developmental context should be considered when examining the effects of early onset of drinking. Thus, if early onset of alcohol use is part of a larger environmental and behavioral risk pathway leading to alcohol dependence, then it may be that the onset-dependence relation is only a reflection of this larger matrix of risk factors.