Signs and symptoms of prescription drug abuse depend on the specific drug. Because of their mind-altering properties, the most commonly abused prescription drugs are:

• Opioids used to treat pain, for example medications containing oxycodone — such as Oxycontin and Percocet — and those containing hydrocodone — such as Norco

• Anti-anxiety medications and sedatives, such as alprazolam (Xanax) and diazepam (Valium), and hypnotics, such as zolpidem (Ambien), used to treat anxiety and sleep disorders

• Stimulants, such as methylphenidate (Ritalin, Concerta, others), dextroamphetamine and amphetamine (Adderall XR, Mydayis), and dextroamphetamine (Dexedrine), used to treat attention-deficit/hyperactivity disorder (ADHD) and certain sleep disorders

Other signs include:

• Stealing, forging or selling prescriptions

• Taking higher doses than prescribed

• Excessive mood swings or hostility

• Increase or decrease in sleep

• Poor decision-making

• Appearing to be high, unusually energetic or revved up, or sedated

• Requesting early refills or continually "losing" prescriptions, so more prescriptions must be written

• Seeking prescriptions from more than one doctor

Teens and adults abuse prescription drugs for many reasons, such as:

• To feel good or get high

• To relax or relieve tension

• To reduce appetite or increase alertness

• To experiment with the mental effects of the substance

• To maintain an addiction and prevent withdrawal

• To be accepted by peers or to be social

• To try to improve concentration and academic or work performance

Some people fear that they may become addicted to medications prescribed for medical conditions, such as painkillers prescribed after surgery. But you can reduce your risk by carefully following your doctor's instructions on how to take your medication.

Prescription drug abuse can happen at any age, but commonly begins in teens or young adults.

Risk factors for prescription drug abuse include:

• Past or present addictions to other substances, including alcohol and tobacco

• Family history of substance abuse problems

• Certain pre-existing psychiatric conditions

• Exposure to peer pressure or a social environment where there's drug use

• Easier access to prescription drugs, such as having prescription medications in the home medicine cabinet

• Lack of knowledge about prescription drugs and their potential harm

Older adults and prescription drug abuse

Prescription drug abuse in older adults is a growing problem, especially when they combine drugs with alcohol. Having multiple health problems and taking multiple drugs can put seniors at risk of misusing drugs or becoming addicted.

Abusing prescription drugs can cause a number of problems. Prescription drugs can be especially dangerous — and even lead to death — when taken in high doses, when combined with other prescription drugs or certain over-the-counter medications, or when taken with alcohol or illegal or recreational drugs.

Medical consequences

Here are examples of serious consequences of prescription drug abuse:

• Opioids can cause low blood pressure, a slowed breathing rate and potential for breathing to stop, or a coma. Overdose has a significant risk of death.

• Anti-anxiety medications and sedatives can cause memory problems, low blood pressure and slowed breathing. Overdose can cause coma or death. Abruptly stopping the medication may cause withdrawal symptoms that can include nervous system hyperactivity and seizures.

• Stimulants can cause dangerously high body temperature, heart problems, high blood pressure, seizures or tremors, hallucinations, aggressiveness, and paranoia.

Physical dependence and addiction

Because commonly abused prescription drugs activate the brain's reward center, it's possible to develop physical dependence and addiction.

• Physical dependence. Physical dependence (also called tolerance) is the body's response to long-term use. People who are physically dependent on a drug may need higher doses to get the same effects and may experience withdrawal symptoms when cutting back or abruptly stopping the drug. Physical dependence may also become evident if a drug the body becomes adjusted to over time, even without dosage change, is stopped abruptly.

• Addiction. People who are addicted to a drug can have physical dependence, but they also compulsively seek a drug and continue to use it even when that drug causes significant problems in their lives.

Other consequences

Other potential consequences include:

• Engaging in risky behaviors because of poor judgment

• Using illegal or recreational drugs

• Being involved in crime

• Motor vehicle accidents

• Decreased academic or work performance

• Troubled relationships