What is Prescription Drug Misuse?
Prescription drug misuse1 is "use of a medication (for a medical purpose) other than as directed or as indicated, whether willful or unintentional, and whether harm results or not." Prescription drug abuse is "any use of an illegal drug; the intentional self-administration of a medication for a nonmedical purpose such as altering one’s state of consciousness, e.g., getting high."
1 Katz NP, Adams EH, Chilcoat H, Colucci RD, Comer SD, Goliber P, et al. (2007). Challenges in the Development of Prescription Opioid Abuse-deterrent Formulations. Clin J Pain. 23(8):648-660.