This Discussion Paper, prepared by UNODC, aligns with key international policy frameworks, including Commission on Narcotic Drugs (CND) resolutions 59/4 and 64/3. These resolutions emphasise the development and dissemination of international standards for the treatment of drug use disorders, as well as the promotion of scientific, evidence-based, affordable, and high-quality approaches to drug prevention, treatment, sustained recovery , and related support services. The paper builds on these mandates to provide an in-depth overview of current knowledge and practice in the field of substance use...