LAUSR

Background Chemsex typically involves drugs such as GHB/GBL, crystal meth and mephedrone, and is increasingly common among MSM. The behaviour has been found to be associated with sexually transmitted infections (STIs) and mental health problems. We aimed to assess the extent of chemsex engagement and associations with different aspects of health, among MSM attending a free specialist walk-in clinic for STIs in Oslo, Norway. Methods Anonymous cross-sectional survey data was collected from June to October 2016. Differences in STI health (chlamydia, gonorrhoea, syphilis, HIV diagnoses), mental health (depression/anxiety) and internalised homonegativity between MSM using and not using GHB/GBL, crystal meth, mephedrone, cocaine or ketamine with sex in the last year were assessed descriptively and in a multivariate logistic regression model. The predictors were number of self-reported chlamydia, gonorrhoea or syphilis diagnoses, HIV diagnosis, depression/anxiety, and degree of internalised homonegativity. We adjusted for age, education level and having lived abroad. Results Of the 518 MSM respondents, 17% reported sexualised use of either GHB/GBL, crystal meth, mephedrone, cocaine or ketamine in the last year (chemsex). We found significant positive associations between chemsex and self-reported HIV diagnoses (adjusted odds ratio [aOR] = 3.26, 95%CI = 1.37–7.76), number of reported chlamydia, gonorrhoea or syphilis diagnoses in the last year (aOR = 1.63, 95%CI = 1.18–2.12), having lived more than one year abroad (aOR = 2.10, 95%CI = 1.20–3.65), but no significant association with depression/anxiety (aOR = 1.02, 95%CI = 0.53–1.93), nor internalised homonegativity (aOR = 0.62, 95%CI = 0.33–1.19). Conclusion Chemsex engagement in Norway is relatively low compared to findings from STI clinics in other European countries, and GHB/GBL and cocaine the two most commonly used drugs with sex. Chemsex was more common among MSM having lived more than one year abroad, reporting HIV diagnoses and a higher number of either chlamydia, gonorrhoea or syphilis diagnoses in the last year. Health care providers need to be made aware of chemsex as a behavioural phenomenon among MSM, and special care should be afforded to MSM living with HIV and being diagnosed with STIs.