It is also striking that the association between GABRA2 and sensation-seeking scores and extraversion is found in the adolescent sample, but not in the young adult sample. Although personality was once thought to reflect stable trait-like characteristics, recent research has demonstrated personality changes across development, with emerging adulthood being a particularly important period (Little-field & Sher, 2010; Littlefield et al., 2009). Impulsivity generally decreases across this period, as more individuals take on adult roles and responsibilities (Littlefield et al., 2010). Accordingly, sensation-seeking behavior in emerging adulthood may reflect a different process than sensation-seeking behavior in adolescence. Optimal levels of sensation-seeking likely vary by developmental stage. Some degree of exploratory behavior is an important component of human development, particularly for a developing adolescent. Accordingly, the fact that GABRA2 is most strongly associated with sensation-seeking behavior in adolescence is an important reminder that this is not a gene for alcohol dependence. Rather, our findings suggest that GABRA2 may alter eventual risk for alcohol-related problems through developmental processes that start early in development with elevated levels of sensation-seeking. These findings also have implications
