Narcotic drugs are classified into two groups.
1 .- Opium and its derivatives, Morphine, Narcotine, Papaverine, and Codeine.
2 .- Their synthetic equivalents, such as Methadone.
Originally it was thought that each of these drugs was not addictive. Subsequently it was shown that all narcotics cause addiction.
(Edited by María Moya Guirao, M.D.)