This document discusses substance use, misuse, and dependence. It defines rational drug use and provides terminology related to drug use. Common substances that are misused like cannabis, cocaine, and heroin are listed along with their effects. Factors that can underlie misuse include perceived benefits and altering one's psychological state. Adverse impacts include health problems, social problems, and drug-related crime. The document also discusses concepts like tolerance, withdrawal, harm reduction, and the roles of pharmacists and pharmacotherapy in addressing drug dependence.