Using a prescription medication without one’s own prescription or in a way that differs from the prescriber’s directions. Examples include taking someone else’s medication, taking a higher dose than directed, or using it for its effects. This can involve prescription opioids, sedatives or stimulants. The term describes a pattern of use; it does not, by itself, mean that the person has a substance use disorder. samhsa.gov
Sources: SAMHSA; Recovery Research Institute