Background: The WHO Comprehensive Mental Health Action Plan 2013-2030 encourages routine collection and reporting of a set of essential mental health indicators, including the availability of psychotropic medicines. The global monitoring of country-level psychotropic medicine consumption trends can provide information on the extent of the availability of psychotropic medicines. The primary objective of this study was to investigate global trends in psychotropic medicines consumption from 2008 to 2019 across 65 countries and regions according to country income level and geographical region., Methods: In this longitudinal trends study, we used pharmaceutical sales data from the IQVIA-Multinational Integrated Data Analysis System (IQVIA-MIDAS). We analysed monthly sales data of psychotropic medicines between Jan 1, 2008, and Dec 31, 2019. Total psychotropic medicine consumption included sales of antidepressants, antipsychotics, tranquilisers, sedatives or hypnotics, and mood stabilisers. Population estimates of each country or region (eight lower-middle-income countries, 19 upper-middle-income countries, and 38 high-income countries) were based on the UN World Population Prospects 2019 report. Average annual sales trends of psychotropic medicines, expressed as defined daily dose (DDD) per 1000 inhabitants per day, were estimated using a random-effects model adjusted for income level and region. Relative changes in the annual consumption of psychotropic medicines by income, expressed as DDD per 1000 inhabitants per day, were assessed as percentage change for each medicine class., Findings: Psychotropic medicine sales increased from 28·54 DDD per 1000 inhabitants per day in 2008 to 34·77 DDD per 1000 inhabitants per day in 2019, corresponding to a 4·08% (95% CI 2·96-5·21) relative average increase annually. The absolute annual increase was greater in high-income countries (3·31 DDD per 1000 inhabitants per day, 95% CI 3·01-3·61) compared with upper-middle-income countries (1·94 DDD per 1000 inhabitants per day, 1·45-2·44) and low-middle-income countries (0·88 DDD per 1000 inhabitants per day, 0·62-1·13; p<0·0001). The relative average annual increase in psychotropic medicine sales from 2008 to 2019 was greater in upper-middle-income countries (7·88%, 95% CI 6·99-8·77) than in lower-middle-income countries (2·90%, 2·40-3·39) and high-income countries (1·02%, 0·80-1·24). In 2019, the regional consumption of psychotropic medicines varied greatly, with the highest sales of all psychotropic medicine classes reported in northern America (167·54 DDD per 1000 inhabitants per day) and lowest sales reported in Asia (5·59 DDD per 1000 inhabitants per day). 17 countries had very low consumption of psychotropic medicines in 2019, including high-income countries and countries with a high prevalence of mental disorders., Interpretation: The consumption of psychotropic medicines has increased over a 12-year period, and although the absolute growth rate was highest in high-income countries, the relative growth is highest in middle-income countries and especially upper-middle-income countries. Disparities in psychotropic medicine consumption of countries can only partly be explained by geographical location and income. Greater efforts are needed to increase the availability of psychotropic medicines in countries with very low consumption, which is probably due to financial or cultural reasons as well as scarcity of trained health-care professionals to prescribe psychotropic medicines., Funding: None., Competing Interests: Declaration of interests JEB is supported by the Hong Kong Research Grants Council as a recipient of the Hong Kong PhD Fellowship Scheme. JFH is supported by the Wellcome Trust (211085/Z/18/Z), the University College London Hospitals National Institute for Health Research (NIHR) Biomedical Research Centre (London, UK), and the NIHR North Thames Applied Research Collaboration. KKCM is the recipient of the CW Maplethorpe Fellowship, reports grants from the NIHR and the Hong Kong Research Grant Council, and reports personal fees from IQVIA, unrelated to the submitted work. EWC has received an honorarium from the Hong Kong Hospital Authority, and research grants from the Hong Kong Research Grants Council, the Hong Kong Research Fund Secretariat of the Food and Health Bureau, the National Natural Science Fund of China, the Australian National Health and Medical Research Council, the Wellcome Trust, Bayer, Bristol Myers Squibb, Pfizer, Janssen, Amgen, Takeda, and the Hong Kong Narcotics Division of the Security Bureau, outside the submitted work. CSLC has received grants from the Food and Health Bureau of the Hong Kong Government, the Hong Kong Research Grant Council, the Hong Kong Innovation and Technology Commission, Pfizer, IQVIA, and Amgen, and personal fees from Primevigilance, outside the submitted work. ICKW reports research funding outside the submitted work from Amgen, Bristol Myers Squibb, Pfizer, Janssen, Bayer, GSK, Novartis, the Hong Kong Research Grants Council, the Hong Kong Health and Medical Research Fund, the NIHR, the European Commission, and the Australian National Health and Medical Research Council, and has also received expert testimony payment from the Hong Kong Court of Final Appeal and speaker's fees from Janssen and Medice in the previous 3 years. All other authors declare no competing interests., (Copyright © 2021 Elsevier Ltd. All rights reserved.)