This study combines desk reviews and key informant in-depth interview analysis. We conducted desk reviews of relevant published drug policy manuscripts and legislative documents to understand the development of drug policies addressing illicit drug prevention and treatment in general and ATS specifically in Vietnam. We obtained those manuscripts by searching Medline (separately EBSCOhost and PubMed), Web of Science, and Google Scholar databases. Further, we retrieved the legal and regulatory documents from Vietnam’s legal databases (thuvienphapluat.vn) and the websites of Ministry of Health (MOH), Ministry of Labour, Invalids and Social Affairs (MOLISA), and Ministry of Public Security (MPS) in Vietnam. As a result, 25 relevant published manuscripts and 51 law and policy documents were included and analysed in full text in the Vietnamese language by two bilingual researchers.

Key informants (KIs) in-depth interviews were conducted in two rounds to improve understanding of drug policy implementation and reveal constraints regarding contemporary management of ATS misuse nationally. KIs were selected purposely based on the sample frame of key agencies suggested by the Addiction Treatment Network members in Vietnam. The sample inclusion criteria were: (1) participants were drug control policymakers or treatment specialists who had worked for at least five years within areas responsible for substance abuse law, policies, prevention programs, and treatment in Vietnam. Collectively, these participants were deemed to have broad knowledge about drug policies in Vietnam and recent experience working with people who use ATS; (2) participants held managerial roles in governmental or non-governmental organisations responsible for developing and implementing legal documents or providing services to people who use drugs in Vietnam. Twenty-three persons identified as key informants were invited by phone and email, of whom 22 agreed to participate in face-to-face interviews that were conducted from December 2020 to May 2021.