Another characteristic associated with both LR and alcohol outcomes is heavier drinking and drug use earlier in life (Schulenberg & Maggs, 2008; Trim et al, 2008). The intake of alcohol can decrease the LR to alcohol, perhaps through the development of tolerance, and prior substance use patterns have been used as covariates in evaluations of LR (Eng et al., 2005; Schuckit & Gold, 1988). A person’s age is also important because the risk for heavy drinking and AUDs increases during adolescence and subsequently diminishes after age 30 (Hingson et al., 2008; Nelson et al., 1998), and the average age of onset of alcohol dependence is in the mid-20’s, although earlier problems are likely to be seen for men with preexisting antisocial problems (Liu et al., 2004; Ohannessian & Hesselbrock, 1993; Schuckit et al., 1998; Schuckit & Smith, 2001; Slutsky et al., 1998). Increasing age can also relate to a higher LR through higher blood alcohol concentrations (BACs) per drink due to higher body fat (with lower proportions of body water), slightly slower metabolism of alcohol, and increased brain sensitivity to depressant drugs with advancing age (Kalant, 1998; Lynsky et al., 2003; Wang et al., 2001).
