The chapter on substance use prevalence and patterns focuses on alcohol, tobacco, and other drugs, including marijuana, cocaine, and psychotherapeutics/stimulants, drawing upon national and regional surveys. Correlates and risk factors may include any combination of the following: age at onset; appropriateness, gender role norms, and expectations; coping, stress, and depression; dating and sociability; decisionmaking factors; educational attachment; family factors such as family bonds and management, family composition, parental attitude, and parental drug use; peer pressure; self-concept; sexual behavior; and patterns of abuse. Some implications for prevention and intervention relate to context of use, differential effects, information dissemination, educational attachment, family education, peer pressure, resistance skills, risk reduction, self-esteem enhancement, sexual abuse and sexual behavior, stress reduction and coping skills, and targeting high-risk populations.