using more detailed assessments, including thorough timing and duration of exposure. Third, as with any cross-sectional study, the results are limited to a particular developmental period, in this case early to late adolescence. Further investigations are needed to determine whether the same relationships hold at both earlier (childhood) and later (adulthood) developmental periods. This is particularly important given recent work by Molina and colleagues (2007) who demonstrated that childhood ADHD predicted heavy drinking, drunkenness, alcohol use disorder symptoms and alcohol use disorder for late adolescence but not for early adolescence. Further evidence for considering additional developmental stages, can be found in a genetic association study by Dick et al (2006) who show that the GABRA2 gene is significantly associated with childhood CD symptoms but not with childhood alcohol dependence symptoms. However, they do show a consistent elevation in risk for alcohol dependence that is associated with GABRA2, but this association only becomes evident in the mid-20s and then remains throughout adulthood (Dick et al., 2006).
