Prescription drug abuse is the use of prescription drugs — most commonly painkillers, sedatives and stimulants — in ways not intended by the prescribing physician. Prescription drug abuse includes everything from seeing multiple doctors to obtain prescriptions, exaggerating or making up ailments to obtain prescriptions, increasing dose and frequency in order to feel the effects of the medication, taking a friend's prescription painkiller, to snorting ground-up pills for faster effect.

In general, the following behaviors are warning signs of prescription drug abuse:

• Continually "losing" prescriptions, so more prescriptions must be written
• Seeking prescriptions from more than one doctor
• Taking higher doses despite warnings
• Taking medication more frequently than prescribed
• Stealing, forging or selling prescriptions
• Taking medication prescribed for someone else
• Excessive mood swings

Symptoms by type of drug
The most commonly abused prescription drugs are:

• Opioid painkillers, such as oxycodone (OxyContin) and those containing hydrocodone (Vicodin)
• Sedatives and tranquilizers, such as diazepam (Valium) and lorazepam (Ativan)
• Stimulants, such as methylphenidate (Ritalin) — commonly used to treat attention-deficit/hyperactivity disorder (ADHD)

Information obtained from the Foundation for a Drug-Free World.