Opioids are a class of drugs used to reduce pain. Legal opioids include prescription painkillers such as oxycodone (OxyContin), hydrocodone (Vicodin), and morphine as well fentanyl, a much more powerful synthetic opioid used to treat severe pain. Abuse of legal opioids often leads to abuse of the illegal opioid heroin.

Prescription opioids work to dampen pain signals from the body, but they also produce psychological effects like euphoria and extreme relaxation. These intensely “rewarding” side effects are what contribute to the development of drug abuse and addiction.

Over time, frequent use of opioids at increasingly high doses elicits persistent alterations to a user’s brain chemistry that may compel them to use the drug even without the presence of pain that originally necessitated their use. Essentially, this pattern of use tricks the brain into believing that taking high doses of these drugs is good for you.