Opioid addiction is a complex condition that is caused by changes in the brain’s chemistry and circuitry. When a person uses opioids, such as prescription painkillers or heroin, they bind to the brain’s opioid receptors, which are responsible for regulating pain, pleasure, and reward. This causes the brain to release a surge of dopamine, a neurotransmitter associated with pleasure and reward. Over time, the brain becomes dependent on the opioids to release dopamine and to feel pleasure and reward. As a result, the person’s brain and behavior change, leading to addiction.
Opioid addiction is characterized by compulsive drug-seeking behavior, even in the face of negative consequences. People with opioid addiction may experience withdrawal symptoms when they try to stop using the drug, including pain, anxiety, insomnia, and gastrointestinal distress. These symptoms can be so severe that they lead the person to continue using opioids to avoid them.