What is prescription drug abuse?

Most people use prescription medications responsibly, but a growing number are taking certain classes of these drugs for nonmedical reasons—a phenomenon the National Institute on Drug Abuse (NIDA) refers to as "prescription drug abuse." In fact, nationwide, about one in five people reports using prescription drugs for nonmedical reasons at some point in his or her lifetime. However, abuse in this context doesn't correspond to the definition that appears in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Rather, it means any use that is outside the medically prescribed regimen, such as taking a different dose, getting the drug from a nonmedical source (a relative, friend, or Internet seller), or taking the drug for its psychoactive effects. The three classes of medications that are most often abused are opioids (powerful painkilling drugs), depressants, and stimulants.