Prescription and illegal opioids are commonly abused because they are so addictive. <br /><br />Opioid medications bind to the areas of the brain that control pain and emotions, driving up levels of the feel-good hormone dopamine in the brain's reward areas and producing an intense feeling of euphoria.<br /><br />As the brain becomes used to the feelings, it often takes more and more of the drug to produce the same levels of pain relief and well-being, leading to dependence and, later, addiction.