Chemsex behaviours among men who have sex with men: A systematic review of the literature

Background‘Chemsex’ is the use of drugs before or during planned sexual events to facilitate, enhance, prolong and sustain the experience. Drugs associated with chemsex are methamphetamine, GHB/GBL, mephedrone, cocaine and ketamine. This review syntheses published research on the antecedents, behaviours and consequences associated with chemsex behaviours among men who have sex with men (MSM).MethodsPapers from high income countries which were published between January 2000 and September 2018 reporting the use of chemsex drugs before or during sex were identified through Medline, Web of Science, CINAHL and Central. Results were synthesised using a narrative approach and conceptualised using a behavioural analysis framework.ResultsThe search identified 2492 publications, of which 38 were included in the final synthesis. There were wide variations in chemsex prevalence estimates due to the heterogeneous sampling in the studies. Chemsex participants have expectations that the drugs will positively affect their sexual encounters and HIV positive MSM are more likely to engage in the behaviour than HIV negative MSM. There were wide ranging prevalence estimates on injecting drugs for sexual purposes and the sharing of injecting equipment with some evidence of unsafe injecting practices. Participants were more likely to engage in condomless anal intercourse than men who do not engage in chemsex. This may increase the risk of transmission for HIV and other sexually transmitted infections.ConclusionA minority of MSM appear to engage in chemsex behaviours but they are at risk of this negatively impacting on their health and well-being. Further research is required to examine high risk chemsex behaviours, impact of chemsex on psycho-social well-being and if chemsex influences uptake of PrEP, PEP and sexual health screening.     

Poly drug use,chemsex drug use,and associations with sexual risk behaviour in HIV-negative men who have sex with men attending sexual health clinics

BackgroundRecreational drug use and associated harms continue to be of significant concern in men who have sex with men (MSM) particularly in the context of HIV and STI transmission.MethodsData from 1484 HIV-negative or undiagnosed MSM included in the AURAH study, a cross-sectional, self-completed questionnaire study of 2630 individuals from 20 sexual health clinics in the United Kingdom in 2013–2014, was analysed. Two measures of recreational drug use in the previous three months were defined; (i) polydrug use (use of 3 or more recreational drugs) and (ii) chemsex drug use (use of mephedrone, crystal methamphetamine or GHB/GBL). Associations of socio-demographic, health and lifestyle factors with drug use, and associations of drug use with sexual behaviour, were investigated.ResultsOf the 1484 MSM, 350 (23.6%) reported polydrug use and 324 (21.8%) reported chemsex drug use in the past three months. Overall 852 (57.5%) men reported condomless sex in the past three months; 430 (29.0%) had CLS with ≥2 partners, 474 (31.9%) had CLS with unknown/HIV+ partner(s); 187 (12.6%) had receptive CLS with an unknown status partner. For polydrug use, prevalence ratios (95% confidence interval) for association with CLS measures, adjusted for socio-demographic factors were: 1.38 (1.26, 1.51) for CLS; 2.11 (1.80, 2.47) for CLS with ≥2 partners; 1.89 (1.63, 2.19) for CLS with unknown/HIV+ partner(s); 1.36 (1.00, 1.83) for receptive CLS with an unknown status partner. Corresponding adjusted prevalence ratios for chemsex drug use were: 1.38 (1.26, 1.52); 2.07 (1.76, 2.43); 1.88 (1.62, 2.19); 1.49 (1.10, 2.02). Polydrug and chemsex drug use were also strongly associated with previous STI, PEP use, group sex and high number of new sexual partners. Associations remained with little attenuation after further adjustment for depressive symptoms and alcohol intake.ConclusionThere was a high prevalence of polydrug use and chemsex drug use among HIV negative MSM attending UK sexual health clinics. Drug use was strongly associated with sexual behaviours linked to risk of acquisition of STIs and HIV.     

Illicit drug use among gay and bisexual men in 44 cities: Findings from the European MSM Internet Survey (EMIS)

BackgroundAnecdotal evidence suggests that men who have sex with men (MSM) are increasingly combining sex and illicit drugs (an activity referred to as ‘chemsex’), in particular GHB/GBL, ketamine, crystal meth, or mephedrone (here called 4-chems). Use of such drugs has been associated with mental health and sexual health harms. We aim to compare patterns of illicit drug use among MSM in 44 European urban centres.MethodsIn 2010, EMIS recruited 174,209 men from 38 countries to an anonymous online questionnaire in 25 languages. As harm reduction services for drugs and sex are organised at a local level, we chose to compare cities rather than countries. We defined 44 cities based on region/postal code and settlement size. For multivariable regression analyses, three comparison groups of MSM not living in these cities were applied: MSM living in Germany, the UK, and elsewhere in Europe.ResultsData from 55,446 MSM living in 44 urban centres were included. Use of 4-chems (past 4 weeks) was highest in Brighton (16.3%), Manchester (15.5%), London (13.2%), Amsterdam (11.2%), Barcelona (7.9%), Zurich (7.0%) and Berlin (5.3%). It was lowest in Sofia (0.4%). The rank order was largely consistent when controlling for age, HIV diagnosis, and number of sexual partners. City of residence was the strongest demographic predictor of chemsex-drug use.ConclusionUse of drugs associated with chemsex among MSM varies substantially across European cities. As city is the strongest predictor of chemsex-drug use, effective harm reduction programmes must include structural as well as individual interventions.     

Microscopic Models of Drug/Chemical Diffusion Through the Skin Barrier: Effects of Diffusional Anisotropy of the Intercellular Lipid

Owing to the systematic alignment and ordering of fatty acid and ceramide chains, lipid layers in biological membranes have strongly anisotropic diffusion properties. The diffusivity $D_{\parallel }^{\mathrm{lip}}$ for solute transport in the direction parallel to the lipid layer is typically 10³-10⁵ times the diffusivity $D_{\perp }^{\mathrm{lip}}$ for the perpendicular direction. This article explores the consequences of this strong degree of anisotropy on solute diffusion through the stratum corneum (barrier) layer of the skin based on a realistic representation of a unit cell of the microstructure. Complementary numerical methods (smoothed particle hydrodynamics, finite differences) are used to solve the steady-state unit-cell diffusion problem leading to the average (homogenized, coarse-grained) diffusion tensor characterizing the tissue as an effective continuum. A parametric study is presented characterizing solute concentration profiles in detail for testosterone- and caffeine-like permeants, and it is shown that the results cannot be mimicked by calculations based on an isotropic lipid-phase diffusivity. The ratio of lateral to transdermal effective diffusivities calculated by the present model is of the order of 40 and 300 for fully hydrated (in vitro) and partially hydrated (in vivo) states, respectively. These values compare favorably with the results of recent experiments.