Participants were randomly selected from nine senior high schools representative of urban and rural districts in western Oregon. A total of 1,709 adolescents completed the initial (T1) assessments (interview and questionnaire) between 1987 and 1989, with an overall participation rate of 61 percent. At the second (T2) assessment 1 year later, 1,507 participants (88.1 percent of T1 respondents) returned for a readministration of the interview and questionnaire. Adolescents were interviewed at T1 with a version of the Schedule for Affective Disorders and Schizophrenia for School-Age Children. Enough information was collected in both the T1 and T2 interviews to ascertain the symptom patterns of alcohol abuse and dependency as per DSM-IV criteria. Findings show that three-quarters of the sample had tried alcohol. Boys in general had greater usual frequency and quantity of alcohol consumption than girls and began drinking at an earlier age; girls with a diagnosis of alcohol abuse/dependence had a significantly earlier mean age of alcohol disorder onset and were more likely to have a relapse of alcohol disorder; however, gender differences in symptom prevalence were insignificant. Seventeen percent of the sample had at least one alcohol abuse/dependence symptom. The most frequent symptoms included reduced activities because of alcohol use, consumed more than intended, and tolerance. Eight of the 11 symptoms made a unique contribution to the prediction of diagnosis in a multiple logistic regression analysis. Components analysis supported the general division of symptoms into the categories of abuse and dependence. 4 tables, 3 figures, and 49 references