(drug addiction) Chronic compulsive drug seeking and continued use despite harmful consequences.

(drug addiction) State of heavy dependence on any drug, including alcohol; sometimes defined as physical dependence but usually also including emotional dependence, i.e., compulsive or pathological drug use.

Drug dependence - replaced the term "drug addiction" and is defined as a state, psychic and sometimes also physical, resulting from the interaction between a living organism and a drug, characterized by behavioral and other responses that always include a compulsion to take the drug on a continuous or periodic basis in order to experience its psychic effects, and sometimes to avoid the discomfort of its absence. Tolerance may or may not be present. A person may be dependent on more than one drug.

Drug addiction, also called substance use disorder, is a disease that affects a person's brain and behavior and leads to an inability to control the use of a legal or illegal drug or medication. Substances such as alcohol, marijuana and nicotine also are considered drugs. When you're addicted, you may continue using the drug despite the...