This document discusses the application of health psychology and prevention of health problems. It specifically discusses cigarette smoking, alcohol use, and weight control. Regarding cigarette smoking, it discusses reasons why people smoke despite health risks and various techniques used to help people quit smoking. It notes high relapse rates and that prevention by deterring youth from starting is most effective. For alcohol, it discusses prevalence of drinking, health risks of heavy use, and various treatment approaches for alcohol abuse/dependence that have high relapse rates. Controlled drinking is a controversial treatment approach.