Definitions related to the medical use of opioids: evolution towards universal agreement.

Misunderstandings regarding the nature and occurrence of addiction have historically been barriers to the appropriate treatment of pain and have stigmatized the medical use of opioids. This article reviews the evolution of nomenclature related to addiction, presents current scientific understanding of addiction that may help shape universally acceptable terminology, and discusses an integrated effort of pain and addiction professionals to reach consensus on addiction-related terms. The article suggests key principles that may clarify terminology including: clear differentiation of the concepts of addiction and physical dependence, conceptualization of addiction as a multidimensional disease, and use of a label for the phenomenon of addiction that does not include the ambiguous term "dependence." More universal agreement on terminology related to addiction is expected to improve the treatment of both pain and addictive disorders; improve communication between health care providers, regulators, and enforcement agencies; and reduce health care and other societal costs.