Table 1.

Definitions of abuse and misuse.

Agency	Definition of “abuse”	Definition of “misuse”
World Health Organization [72]	Persistent or sporadic excessive drug use inconsistent with or unrelated to acceptable medical practice.	Use of a substance for a purpose not consistent with legal or medical guidelines, as in the nonmedical use of prescription medications.
Food and Drug Administration [73,74]	The nonmedical use of a drug, repeatedly or even sporadically, for the positive psychoactive effects it produces.	The use of a drug outside label directions or in a way other than prescribed or directed by a health care practitioner. This definition includes patients using a drug for a condition different from that for which the drug is prescribed, patients taking more drug than prescribed or at different dosing intervals, and individuals using a drug not prescribed for them, although for therapeutic purposes.