The study uses structured interview and diagnostic assessment in order to identify risk factors for and measure the prevalence of alcohol abuse, drug abuse, and psychopathology for 523 Indian youth and 27 Indian women. Six independent cohorts compose the study population. Cohort 1 consisted of 224 American-Indian youth recruited from the fifth and sixth grades of 2 urban school districts during the 1988-89 academic year. This cohort is assessed annually and will complete nine interviews during Phase I and Phase II of the project. Cohort 2 consists of 66 subjects recruited from the membership of the local Indian Health Board while they were enrolled in the fifth and sixth grades during the 1988-89 academic year. Cohorts 1 and 2 have similar mean ages and follow the same assessment schedule. Cohort 3 consists of 78 youth recruited during the 1992-93 academic year from the 9th and 10th grades of the same 2 school districts as Cohort 1. Cohort 3 will complete five annual interviews during Phase II. If demographic and behavior comparisons show adequate homogeneity, they will be added to Cohort 1 in order to minimize statistical power issues that could arise due to attrition. Cohort 4 is composed of 76 ninth graders recruited during the 1989-90 academic year, and Cohort 5 consists of 78 sixth graders recruited during the 1990-91 academic year. Each cross sectional cohort is scheduled to complete two additional interviews during Phase II. Cohort 6 is composed of 276 American-Indian women, mostly the biological mothers of the 5 youth cohorts. 6 tables, 5 figures, and 86 references