Substance Dependence

Substance dependence refers to a physiological and psychological dependency on a drug. Various drug categories are associated with a unique set of potential consequences and dependence potential. For example, some drugs are likely to have lethal consequences (e.g., opioids) and high potential for biological dependence, whereas others generally do not (e.g., hallucinogens). Alternatively, some drugs that are physiologically addictive generally are not abused (e.g., caffeine) but are used by many individuals across cultures. Many, if not most, drugs can result in an acquired psychological dependence on the drug. Almost all drugs of abuse are highly rewarding because of their influence on reinforcing neurobiological systems, but they do not necessarily result in the experience of "biologically" related withdrawal symptoms, such as physical pain, vomiting, diarrhea, and ...