METHODS: PubMed and Google Scholar were searched for published studies from 2010 to 2020. Searches were conducted by using the relevant country of interest as a search term (e.g. "Iran"), as well as relevant predefined keywords such as "cannabis", "marijuana", "hashish", "bhang "dual diagnosis", "use", "addiction", "prevalence", "co-morbidity", "substance use disorder", "legalization" or "policy" (English and non-English). These keywords were used in multiple combinations to create the search string in studies records' titles and abstracts. Official websites of respective governments and international organizations were also searched in English and non-English (national language country) languages to identify the current state of cannabis use, policies, and research in each of those countries.
RESULTS: Inconsistent and heterogeneous reporting of cannabis use, variation in policies (e.g., legalization), and intervention strategies across the reviewed countries were the main findings. European countries have dominated cannabis research output in PubMed, as compared to Asian countries (Thailand, Malaysia, India, Iran and Nepal).
CONCLUSIONS: Although global cannabis regulation is ongoing, the existing heterogeneities across countries in terms of policies and epidemiology can increase the burden of cannabis use disorders disproportionately and unpredictably. There is an urgent need to develop global strategies to address these cross-country barriers to improve early detection, prevention, and interventions for cannabis use and related disorders.