The Single Convention unambiguously condemns drug addiction, however, stating that "addiction to narcotic drugs constitutes a serious evil for the individual and is fraught with social and economic danger to mankind". It takes a prohibitionist approach to the problem of drug addiction, attempting to stop all non-medical, non-scientific use of narcotic drugs. requires nations to limit use and possession of drugs to medicinal and scientific purposes. allows countries to phase out coca leaf chewing, opium smoking, and other traditional drug uses gradually, but provides that "the use of cannabis for other than medical and scientific purposes must be discontinued as soon as possible."