"Expressed in monetary terms, some US$ 200 billion-250 billion (0.3-0.4 per cent of global GDP) would be needed to cover all costs related to drug treatment worldwide. In reality, the actual amounts spent on treatment for drug abuse are far lower — and less than one in five persons who needs such treatment actually receives it."
Source
UN Office on Drugs and Crime, World Drug Report 2012 (United Nations publication, Sales No. E.12.XI.1), p. 4.
https://www.unodc.org/documen…
