Subjects were excluded from neurophysiological assessment if they had any of the following: (1) recent substance or alcohol use (i.e., positive breath-analyzer test and/or urine screen), (2) hepatic encephalopathy/cirrhosis of the liver, (3) history of head injury, seizures or neurosurgery, (4) uncorrected sensory deficits, (5) history/symptoms of psychoses, (6) self-reported positive test for human immunodeficiency virus, and (7) other acute/chronic medical illnesses that affects brain function. The HR group consisted of individuals from the COGA high density alcoholism families who had at least one parent with DSM-IV alcohol dependence, while the LR group consisted of individuals from the community families without any parental history of alcohol dependence. The groups were further subdivided based on gender and age group (12–15 and 16–25 years old) (see Table 1). As the age distribution was skewed in the overall sample (i.e., relatively more subjects were represented at younger ages), the sample was subdivided into these age groups, in order to provide adequate sample sizes for each age group and ensure good pubertal and post-pubertal representation. Table 2 shows lifetime prevalence rates of externalizing disorders
