• 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.
  • Physical and emotional dependence on a chemical substance. Compare drug dependency.
  • Psychological craving for or habituation to the use of a chemical substance which may or may not be accompanied by physical dependency. Used for animal or human populations. Compare 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.