Chemsex Drugs on the Rise

A Longitudinal Analysis of the Swiss HIV Cohort Study From 2007 to 2017

B Hampel; K Kusejko; RD Kouyos; J Böni; M Flepp; M Stöckle; A Conen; C Béguelin; P Künzler-Heule; D Nicca; AJ Schmidt; H Nguyen; J Delaloye; M Rougemont; E Bernasconi; A Rauch; HF Günthard; DL Braun; J Fehr


HIV Medicine. 2020;21(4):228-239. 

In This Article

Abstract and Introduction


Objectives: Chemsex refers to the use of sex-enhancing drugs among men who have sex with men (MSM) in combination with specific sexual and social behaviours. Longitudinal data on this development and the associated health risks are scarce.

Methods: Data on all recreational drugs reported in the Swiss HIV Cohort Study (SHCS) from 2007 to 2017 were collected. Drug use was analysed longitudinally for all drug classes. In addition, potential associations between patient characteristics and the consumption of methamphetamine, γ-hydroxybutric acid/γ-butyrolactone (GHB/GBL), 3,4-methylenedioxymethamphetamine (MDMA/XTC), cocaine and amphetamine were analysed.

Results: We analysed 166 167 follow-up entries for 12 527 SHCS participants, including 7101 free text field entries containing information about recreational drugs other than cannabis, cocaine and heroin. Overall, we observed a stable percentage (9.0%) of recreational drug use (excluding cannabis, amyl nitrite and prescription drugs). For MSM, however, there was an increase in overall drug use from 8.8% in 2007 to 13.8% in 2017, with particularly large increases for methamphetamine (from 0.2 to 2.4%; P < 0.001) and GHB/GBL (from 1.0 to 3.4%; P < 0.001). The use of each of the potentially sex-enhancing drugs methamphetamine, GHB/GBL, cocaine, XTC/MDMA and amphetamine was significantly associated with condomless sex with nonsteady partners, and higher prevalences of depression, syphilis and hepatitis C.

Conclusions: The significant increase in the use of chemsex drugs among MSM in the SHCS and the strong association with coinfections and depression highlights the need for harm reduction programmes tailored to MSM. According to our results, improving knowledge about recreational drugs is important for all health care professionals working with people living with HIV.


A growing number of reports across multiple countries show a new trend of sex-enhancing drug use among men who have sex with men (MSM), often referred to as chemsex.[1–3] Chemsex defines a syndemic of specific social and sexual behaviours associated with specific recreational drugs ('chems') among MSM before or during sex, wide use of geosocial networking applications (apps) and sex with a high number of partners in a mostly private setting.[1,2] Drugs often referred to as chemsex drugs typically include N-methylamphetamine (methamphetamine), 4-methyl methcathinone (mephedrone), γ-hydroxybutyric acid/γ-butyrolactone (GHB/GBL) and sometimes ketamine.[1,2] For Switzerland, in 2010 the European MSM Survey (EMIS) showed that all of these drugs were already in use by MSM and that 7% of MSM in Zurich reported use of GHB/GBL, ketamine, methamphetamine or mephedrone in the previous 4 weeks.[3] Despite this, the Swiss Federal Office of Public Health (FOPH) in 2015 concluded that there was no significant methamphetamine usage in Switzerland;[4] however, their analysis did not focus on the HIV-positive population or MSM.

In addition to the direct risk of bloodstream transmission of HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV) infection through needle sharing associated with recreational drug use (RDU), RDU itself has been well studied as a risk factor for sexually transmitted infections (STIs) as a consequence of the associated increase in risky sexual behaviours such as condomless sex and having a high number of sexual partners.[5–8] The availability of new substances and the change in sexual behaviour resulting from the use of geosocial networking apps come with new challenges for health care professionals, such as prevention and treatment of infectious and psychiatric diseases.[9–11] This change in sexual behaviour might also be one reason for the growing number of STIs among MSM.[12,13] The extent of this new development has, to date, not been well studied longitudinally.

The aim of this study was to analyse the trend in the consumption of all recreational drugs over the last 11 years among all participants in the Swiss HIV Cohort Study (SHCS), with a particular focus on the use of chemsex drugs and other potentially sex-enhancing drugs among MSM. In addition, we compared characteristics of participants who reported using recreational drugs (excluding cannabis, amyl nitrite and prescription drugs) at least once during the study period to those of participants who did not report RDU at any follow-up visit.