Chemsex, the unfortunately chosen term for sex under the influence of illegal drugs (unfortunate because it connotes chemistry with illegal, when love is clearly a chemistry event in the brain) - needs to become a public health priority, argue experts in The BMJ. This intentional sex under the influence of psychoactive drugs occurs mostly among gay men.

Chemsex usually refers particularly to the use of mephedrone, gamma-hydroxybutyrate (GHB), gamma-butyrolactone (GBL), and crystallized methamphetamine. The drugs are often used in combination to facilitate sexual sessions lasting several hours or even days, with multiple sexual partners.

The authors say the growing frequency of chemsex may be putting participants at even greater risk of HIV and other sexually transmitted infections as well as bringing about serious mental health problems through drug dependence.

Though data on drug use in a sexual context is sparse, employees at Antidote, a specialist drugs service for the lesbian, gay, bisexual, transgender community in London, anecdotally claim that over 60% of attendees seeking support for drug use reported using chemsex drugs in 2013-14. 

Of crystal meth and GHB/GBL users, most reported using them to facilitate sex,
with around three quarters reporting injecting drug use.

The authors argue that drug counseling in the UK is focused on heroin, crack cocaine and alcohol dependency, and they believe referral to traditional services is inappropriate. But without data, various layers of legal and regulatory bureaucracy in their nationalized medicine environment limit the advice clinicians may give. For instance, the National Institute for Health and Care Excellence has provided only limited advice on psychoactive drug use and no specific recommendations relating to chemsex drugs. The Novel Psychoactive Treatment UK Network (Neptune) has published a guidance document for clinicians managing the "harms resulting from the use of club drugs and novel
psychoactive substances."