GABRA2 and alcohol drinking: For example, GABRA2 is associated with alcohol dependence in samples where alcohol-dependent cases came from clinically recruited samples and families densely affected by alcoholism,54, 55, 56 but not community-based samples.57 A sample recruited for this purpose is likely to be enriched for genetic variation that predisposes individuals to a range of externalizing behavior problems, including AAB;18 however, whether our findings generalize to other populations at high risk for AAB (for example, incarcerated inmates58) is unknown.