These findings build on previous results (Littlefield et al., 2009) in several ways. In our previous analyses that utilized a variable-centered approach (i.e., bivariate latent growth modeling; see Littlefield et al., 2009), we found evidence that changes in impulsivity corresponded with changes in alcohol problems from ages 18 to 35, suggesting that personality change may be an important mechanism in the so-called “maturing out” (Winick, 1962) of heavy alcohol involvement (see O'Malley, 2004/2005). Providing further support, clarity, and precision to these results, these findings illustrate a more nuanced relation between dynamic changes in impulsivity and the developmental course of alcohol involvement. For example, these results suggest that individuals high and relatively stable in impulsivity are at an especially increased risk to maintain elevated levels of problematic alcohol involvement during emerging adulthood. Further, although the current data are correlational in nature and thus causal relations between impulsivity and alcohol cannot be adequately resolved, the patterns of covariation among these constructs suggests that alcohol use appears to be a trailing (i.e., occurs as a result of) indicator of impulsivity development (as opposed to leading, etiologic predictors of developmental course; see Sher et al., 2004, for more details).
