Theories of the nature, course, causes and effects of addiction to alcohol and drugs of,abuse. Conditions, processes, and patterns of recovery. Emphasis on physiological, social, learning, and interpersonal models and theories. Natural history of onset, abuse, addiction, and, recovery; effects of intergenerational transmission, genetic predilection, developmental, risk, and sociocultural factors; effects on psychosocial development; impact of culture and gender differences. Implications for treatment.