Most widely abused illegal drug in U.S.
Opiates->e.g., morphine, codeine, and heroin (most highly abused and most addictive opioid). Positive effects include an elevation of mood (“a high”), a sense of euphoria, a decrease in anxiety and pain (analgesic properties), and an increase in self-esteem. Withdrawal symptoms include dysphoric mood, nausea, vomiting, muscle aches, diarrhea, and insomnia. Abrupt withdrawal from opiates can be life threatening.