Changes in recreational drug use, drug use associated with chemsex, and HIV-related behaviours, among HIV-negative men who have sex with men in London and Brighton, 2013-2016.

There have been significant increases in drug use associated with chemsex and some measures of HIV-related behaviours among HIV-negative MSM in the last few years. Changing patterns of drug use and associated behaviours should be monitored to enable sexual health services to plan for the increasingly complex needs of some clients.