The study participants included 443 California youth, ages 9 through 17, and their parents in Los Angeles communities. Research data was obtained from personal interviews with children, teenagers, and their parents. For comparison purposes, the youths were divided into four groups according to past and current use of alcohol or drugs. Multiple regression analysis of the data revealed age, positive father sentiment, number of parentally defined conduct norms and dependence on mother's advice and counsel variables influence adolescent use of substances. The results support the social learning theory by demonstrating that prosocial behaviors are enhanced with clear statement of behavioral expectations accompanied by positive reenforcement. 1 note, 4 tables, and 42 references