Ketamine use among people who regularly use ecstasy and other illicit stimulants in Australia: Trends and characteristics of use, 2009–2019

Objective: Ketamine is a dissociative anesthetic used in medical practice, used recreationally since the mid-1960s. This study describes trends in ketamine use in sentinel cross-sectional samples of Australians who regularly use illicit stimulants, along with characteristics of consumers. Method: Data on trends in recent ketamine use (i.e., use in past 6 months) were drawn from annual interviews (ap-proximately 800/year) with cross-sectional samples of people recruited from Australian state capitals from 2009 to 2019 as part of the Ecstasy and Related Drugs Reporting System (EDRS) study. Characteristics of those reporting recent use were examined in the 2019 EDRS data set (n = 728) using logistic regression. Results: Recent ketamine use increased between 2009 and 2019 (10% to 41%, respectively, p < .001), primarily driven by use among participants recruited in Melbourne (21% to 84%, p < .001) and Sydney (19% to 68%, p < .001). However, frequency of use remained low. In 2019, consumer characteristics associated with use included being born outside of Australia and residing in Sydney or Melbourne (compared with Canberra). Conclusions: Among EDRS participants in Australia, we observed an increase in recent ketamine use between 2009 and 2019, although indicators of potential problematic use remained low. The increase in recent ketamine use was largely driven by increases in Melbourne and Sydney. Further research on drivers of use in these cities is required to effectively inform harm-reduction strategies. (J. Stud. Alcohol Drugs, 82, 188–196, 2021).