Participants were recruited as part of an ongoing longitudinal neuroimaging study. Flyers were mailed to households of local middle schools describing the project, major inclusion criteria, and compensation. Exclusionary criteria were prenatal alcohol (>2 drinks in a week) or any tobacco or illicit drug use; history of chronic medical illness, any neurological or DSM-IV (APA, 1994 ) Axis I disorder other than conduct disorder, loss of consciousness (>2 minutes), or learning disabilities; parental history of bipolar, psychotic, or antisocial personality disorder; sensory problems; and left handedness. In all, 13% of respondents met eligibility criteria. Extensive screening and background data were obtained from each participant, one biological parent, and one other parent or close relative. At baseline, this study included 76 participants, ages 12–14 years, who had minimal substance use (≤6 total lifetime drinks with ≤3 drinks on any occasion; ≤3 lifetime uses of marijuana (>0 for n=5) and none in the past three months; ≤10 lifetime cigarette uses (>0 for n=5); and no history of other intoxicant use). The current study included adolescents who transitioned into heavy (n= 25; 11 females) or moderate (n=11; 2 females) drinking, and those who remained non-users through follow-up (n=40; 16 females; see Table 1). Because this study is ongoing, different follow-up time points were examined, ranging from one to five years (mean=3.6).