Drug - Definition

Ask a question

Definition


A drug is defined as any psychoactive substance capable of modifying psychological and/or physiological functions of an individual, including humor, thought, behavior or emotion. A drug may engender a psychological or physical dependence. Different criteria used to classify a drug are its therapeutic properties, the dependence it causes, and its effects on the central nervous system. It is the legal classification that determines whether a drug is licit or illicit.