The nonmedical use of prescription drugs increased dramatically in the 1990s and remains at high levels. In 2007, approximately 7 million people aged 12 or older reported nonmedical use of a prescription drug. The most commonly abused medications are painkillers (i.e., opioids: 5.2 million people), stimulants (e.g., methylphenidate and amphetamine: 1.2 million), and central nervous system (CNS) depressants (e.g., benzodiazepines: 2.1 million). Like many illicit substances, these drugs alter the brain's activity and can lead to many adverse consequences, including addiction. For example, opioid pain relievers, such as Vicodin or OxyContin, can present similar health risks as do illicit opioids (e.g., heroin) depending on dose, route of administration, combination with other drugs, and other factors. As a result, the increases in nonmedical use have been accompanied by increased emergency room visits, accidental poisonings, and treatment admissions for addiction. Treatments for prescription drugs tend to be similar to those for illicit drugs that affect the same brain systems. Thus, buprenorphine is used to treat addiction to opioid pain medications, and behavioral therapies are most likely to be effective for stimulant or CNS depressant addiction—for which we do not yet have medications.