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


Study Population and Overall Drug use in the SHCS

During the study period 2007–2017, information on cocaine, cannabis and heroin use was available for 12 527 SHCS participants, of whom 5657 (45.2%) were MSM and 6870 (54.8%) were non-MSM (female or heterosexual male). Almost half of all MSM were registered in Zurich (47.2%). Information from 166 167 total visits was available, and, of those, only 2086 (1.3%) visit entries did not contain any information about drug use. Overall, 1840 (14.7%) of the participants reported substance use in the free text field. In detail, we could identify 7101 substances reported at 5840 follow-up visits from these 1840 participants. In total, we identified 408 different spellings of substances reported (see Appendix 1). Overall, 4686 (37.4%) of all SHCS participants reported the intake of any kind of recreational drug at least once during the study period. Excluding cannabis, amyl nitrite, benzodiazepines and other prescription drugs, 2560 (20.4%) of the SHCS participants reported having taken recreational drugs in this period. See Figure 1 for a summary of the drug classes considered.

Figure 1.

The percentage of participants who had used the drug at least once during the follow-up period of 2007–2017. GHB/GBL, γ-hydroxybutric acid/γ-butyrolactone; LSD, lysergic acid diethylamide; XTC/MDMA, 3,4-methylenedioxymethamphetamine.

Time Trend of Drug use in the SHCS

To elucidate the changes in drug use over time, we analysed the typical chemsex drugs GHB/GBL, methamphetamine, ketamine and mephedrone, but also other potentially sex-enhancing drugs used in the SHCS, namely cocaine, XTC/MDMA and amphetamine. We looked at the percentage of SHCS participants using the drugs at least once in each year (Figure 2a). In addition, we looked at the time trend of the proportion of participants reporting drug use, again excluding cannabis, amyl nitrite, benzodiazepines and other prescription drugs. This proportion remained stable, with 9.0% of participants reporting drug use (range 8.6, 9.5%; P for trend = 0.57). However, in contrast to the whole SHCS population, there was a significant increase (P for trend < 0.001) towards more drug use among MSM: the report of drug use increased from 8.8% to 13.8% from 2007 to 2017 (Figure 2b). For non-MSM, we observed the opposite trend (P for trend < 0.001), namely 9.8% reporting drug use in 2007 and 5.7% reporting drug use in 2017 (Figure 2c).

Figure 2.

Time trend of drug use in the SHCS for the whole study population, for MSM and for non-MSM. (a) Percentage of Swiss HIV Cohort Study (SHCS) participants reporting the use of various drugs, by year and drug class. GHB/GBL, γ-hydroxybutric acid/γ-butyrolactone; XTC/MDMA, 3,4-methyleneioxymethamphetamine. (b) The percentage of all men who have sex with men (MSM) participants in the SHCS reporting the use of various drugs, by year and drug class. (c) The percentage of non-MSM participants in the SHCS reporting the use of various drugs, by year and drug class.

Drug use Among MSM

Many of the drug classes considered were predominately taken by MSM, such as XTC/MDMA, GHB/GBL, ketamine and methamphetamine (Figure 1). Data on reported drug use from 5657 MSM for the years 2007–2017 show that 2510 (44.4%) reported drug use at least once during the study period and, if we exclude cannabis, amyl nitrite, benzodiazepines and other prescription drugs, the number remains high at 1468 or 25.9% of all MSM in the study. Analysis of the time trend for chemsex drugs and other potentially sex-enhancing drugs revealed an increase in the use of all these substances (Figure 2b). In particular, when comparing the years 2007 and 2017, we observed an increase in the use of GHB/GBL (from 1.0 to 3.4%; P for trend < 0.001), methamphetamine (from 0.2 to 2.4%; P for trend < 0.001), ketamine (from 0.1 to 0.7%; P for trend = 0.016), mephedrone (from 0.0 to 0.2%; P for trend = 0.006), cocaine (from 6.2 to 9.9%; P for trend < 0.001), XTC/MDMA (from 3.2 to 5.3%; P for trend = 0.0014) and amphetamine (from 0.4 to 1.0%; P for trend < 0.001).

Factors Associated With Drug use

Most participants reporting drug use were from the study centre in Zurich (Figure 3). The total number of participants reporting drug use in the seven SHCS centres as well as patient characteristics can be found in Table 1. A significant association between drug intake and condomless sex with occasional partners was found for the five substances of interest, namely methamphetamine, GHB, cocaine, XTC/MDMA and amphetamine, compared to those MSM not using sex-enhancing drugs (Table 1; Figure 4). All subgroups of drug classes had a significantly higher prevalence of depression. Moreover, adherence to ART was significantly lower for users of GHB/GBL, cocaine and amphetamine compared to the control group. HCV infection and syphilis were more frequent among drug users for all five drug classes considered (Table 1).

Figure 3.

Total number of men who have sex with men (MSM) participants taking chemsex drugs, i.e. γ-hydroxybutric acid/γ-butyrolactone (GHB/GBL), methamphetamine, mephedrone or ketamine, by Swiss HIV Cohort Study (SHCS) centre.

Figure 4.

Analysis of sociodemographic, psychosocial and sexual behaviour measures for men who have sex with men (MSM) reporting drug use of γ-hydroxybutric acid/γ-butyrolactone (GHB/GBL), methamphetamine, cocaine, 3,4-methylenedioxymethamphetamine (XTC/MDMA) and amphetamine in comparison to MSM participants reporting no drug use other than cannabis, amyl nitrite, benzodiazepines and other prescription drugs. In the adjusted analysis, we corrected for the basic sociodemographic factors age, ethnicity and year of diagnosis. adj., adjusted; Univ., univariable.

Data Quality

Health care professionals used a variety of different names to describe the same drug; for example, 72 different spellings/names were used for methamphetamine (Table A1; Appendix 1). In total, we could identify 408 different wording and spellings. Especially for two different substances with similar names, such as methamphetamine and amphetamine, this leads to ambiguity in some cases. Moreover, some entries only vaguely described what substances were taken, such as 'party drugs', and could hence not be used in the analysis of different drug classes. In addition, the health care professionals grouped the drugs into intrevenous and nonintravenus drugs (see Appendix 1). Here, 42 of 811 (5.2%) entries in the category for intrevenous substances belonged to substances that cannot be intrevenous; for example, amyl nitrite, GHB/GBL and MDMA were reported in the intrevenous category, and there were many other entries in this category where injection is unlikely. We were also able to compare the data with as yet unpublished results from the Swiss HCVree trial.[20] In this trial, a subpopulation of 109 participants in the SHCS completed an online questionnaire on recreational drug use during the same study period. Eighty-six of the 109 reported recreational drug use when asked about it in the online questionnaire compared to 33 reports from a one-to-one interview with a health care professional during the SHCS visit.