Opioids have been used for at least 3,500 years, mostly in the form of crude opium or in alcoholic solutions of opium. Morphine was first isolated in 1806 and codeine in 1832. Over the next century, pure morphine and codeine gradually replaced crude opium for medicinal purposes, although nonmedical use of opium (as for smoking) still persists in some parts of the world.

About 90 percent of persons with opioid dependence have an additional psychiatric disorder. The most common comorbid psychiatric diagnoses are major depressive disorder, alcohol use disorders, antisocial personality disorder, and anxiety disorders. About 15 percent of persons with opioid dependence attempt to commit suicide at least once. The high prevalence of comorbidity with other psychiatric diagnoses highlights the need to develop a broad-based treatment program that also addresses patients’ associated psychiatric disorders.