F. F. Hamers and A. M. Downs, The changing face of the HIV epidemic in western Europe: what are the implications for public health policies?, Lancet, vol.364, pp.83-94, 2004.

C. Beyrer, P. Sullivan, and J. Sanchez, The increase in global HIV epidemics in MSM, AIDS, vol.27, pp.2665-2678, 2013.

A. Chaillon, A. Essat, and P. Frange, Spatiotemporal dynamics of HIV-1 transmission in France (1999-2014) and impact of targeted prevention strategies, Retrovirology, vol.14, p.15, 2017.
URL : https://hal.archives-ouvertes.fr/inserm-01473400

C. Wang, Y. Wang, and D. Kong, Characterization of a novel HIV-1 second-generation recombinant form in men who have sex with men in Beijing, China, AIDS Res Hum Retroviruses, vol.33, pp.1175-1179, 2017.

E. M. Volz, N. Ndembi, and R. Nowak, Phylodynamic analysis to inform prevention efforts in mixed HIV epidemics, Virus Evol, vol.3, p.14, 2017.

J. E. Pachankis, M. L. Hatzenbuehler, and R. C. Berg, Anti-LGBT and antiimmigrant structural stigma: an intersectional analysis of sexual minority men's HIV risk when migrating to or within Europe, J Acquir Immune Defic Syndr, vol.76, pp.356-366, 2017.

H. Mccall, N. Adams, and D. Mason, What is chemsex and why does it matter?, BMJ, vol.351, p.5790, 2015.

M. Bracchi, D. Stuart, and R. Castles, Increasing use of 'party drugs' in people living with HIV on antiretrovirals: a concern for patient safety, AIDS, vol.29, pp.1585-1592, 2015.

N. Foureur, S. Fournier, and M. Jauffret-roustide, Premiere enquête qualitative en France

A. J. Schmidt, A. Bourne, and P. Weatherburn, Illicit drug use among gay and bisexual men in 44 cities: findings from the European MSM Internet Survey (EMIS), Int J Drug Policy, vol.38, pp.4-12, 2016.

F. Toates, An integrative theoretical framework for understanding sexual motivation, arousal, and behavior, J Sex Res, vol.46, pp.168-193, 2009.

P. Weatherburn, F. Hickson, and D. Reid, Motivations and values associated with combining sex and illicit drugs ("chemsex") among gay men in South London: findings from a qualitative study, Sex Transm Infect, vol.93, pp.203-206, 2017.

D. Abdulrahim and O. Bowden-jones,

, Guidance on the Management of Acute and Chronic Harms of Club Drugs and Novel Psychoactive Substances. London, United Kingdom: Novel Psychoactive Treatment UK Network (NEPTUNE), 2015.

G. Ireland, S. Higgins, and B. Goorney, Evaluation of hepatitis C testing in men who have sex with men, and associated risk behaviours, Sex Transm Infect, vol.93, pp.404-409, 2017.

A. Bourne, D. Reid, and F. Hickson, Chemsex" and harm reduction need among gay men in South London, Int J Drug Policy, vol.26, pp.1171-1176, 2015.

A. Bourne, D. Reid, and F. Hickson, Illicit drug use in sexual settings ("chemsex") and HIV/STI transmission risk behaviour among gay men in South London: findings from a qualitative study, Sex Transm Infect, vol.91, pp.564-568, 2015.

M. L. Borg, A. Modi, and A. Tostmann, Ongoing outbreak of Shigella flexneri serotype 3a in men who have sex with men in England and Wales, data from, Euro Surveill, p.17, 2009.

A. Hegazi, M. J. Lee, and W. Whittaker, Chemsex and the city: sexualised substance use in gay bisexual and other men who have sex with men attending sexual health clinics, Int J STD AIDS, vol.28, pp.362-366, 2017.

C. H. Hinkin, T. R. Barclay, and S. A. Castellon, Drug use and medication adherence among HIV-1 infected individuals, AIDS Behav, vol.11, pp.185-194, 2007.

C. Marquez, S. J. Mitchell, and C. B. Hare, Methamphetamine use, sexual activity, patient-provider communication, and medication adherence among HIV-infected patients in care, AIDS Care, vol.21, pp.575-582, 2004.

J. C. Hojilla, D. Vlahov, and D. V. Glidden, Skating on thin ice: stimulant use and sub-optimal adherence to HIV pre-exposure prophylaxis, J Int AIDS Soc, vol.21, p.25103, 2018.

J. M. Molina, C. Capitant, and B. Spire, On-demand preexposure prophylaxis in men at high risk for HIV-1 infection, N Engl J Med, vol.373, pp.2237-2246, 2015.
URL : https://hal.archives-ouvertes.fr/halshs-01429281

Z. Ottaway, F. Finnerty, and T. Buckingham, Increasing rates of reported chemsex/sexualised recreational drug use in men who have sex with men attending for postexposure prophylaxis for sexual exposure, Sex Transm Infect, vol.93, p.31, 2017.

J. M. Molina, I. Charreau, and B. Spire, Efficacy, safety, and effect on sexual behaviour of on-demand pre-exposure prophylaxis for HIV in men who have sex with men: an observational cohort study, Lancet HIV, vol.4, pp.402-410, 2017.
URL : https://hal.archives-ouvertes.fr/hal-01963237

M. T. Stephenson, R. H. Hoyle, and P. Palmgreen, Brief measures of sensation seeking for screening and large-scale surveys, Drug Alcohol Depend, vol.72, pp.279-286, 2003.

S. L. Zeger and K. Y. Liang, Longitudinal data analysis for discrete and continuous outcomes, Biometrics, vol.42, pp.121-130, 1986.

S. L. Zeger, K. Y. Liang, and P. S. Albert, Models for longitudinal data: a generalized estimating equation approach, Biometrics, vol.44, pp.1049-1060, 1988.

J. J. Heckman, Sample selection bias as a specification error, Econom J Econom Soc, vol.1979, pp.153-161

C. Protopopescu, F. Raffi, and P. Roux, Factors associated with nonadherence to long-term highly active antiretroviral therapy: a 10 year follow-up analysis with correction for the bias induced by missing data, J Antimicrob Chemother, vol.64, pp.599-606, 2009.

B. J. Shelton, G. H. Gilbert, and Z. Lu, Comparing longitudinal binary outcomes in an observational oral health study, Stat Med, vol.22, pp.2057-2070, 2003.

M. Holt, T. Lea, and H. M. Schmidt, Willingness to use and have sex with men taking HIV pre-exposure prophylaxis (PrEP): results of online surveys of Australian gay and bisexual men, Sex Transm Infect, vol.93, pp.438-444, 2011.

A. Y. Liu, S. E. Cohen, and E. Vittinghoff, Preexposure prophylaxis for HIV infection integrated with municipal-and community-based sexual health services, JAMA Intern Med, vol.176, pp.75-84, 2016.

A. Tomkins, R. Vivancos, and C. Ward, How can those engaging in chemsex best be supported? An online survey to gain intelligence in Greater Manchester, Int J STD AIDS, vol.29, pp.128-134, 2018.

M. Holt, T. Lea, and J. Asselin, The prevalence and correlates of undiagnosed HIV among Australian gay and bisexual men: results of a national, community-based, bio-behavioural survey, J Int AIDS Soc, vol.18, p.20526, 2015.

J. Frankis and D. Clutterbuck, What does the latest research evidence mean for practitioners who work with gay and bisexual men engaging in chemsex, Sex Transm Infect, vol.93, pp.153-154, 2017.

A. K. Ahmed, P. Weatherburn, and D. Reid, Social norms related to combining drugs and sex ("chemsex") among gay men in South London, Int J Drug Policy, vol.38, pp.29-35, 2016.

L. Karila, B. Megarbane, and O. Cottencin, Synthetic cathinones: a new public health problem, Curr Neuropharmacol, vol.13, pp.12-20, 2015.

M. Sande, Characteristics of the use of 3-MMC and other new psychoactive drugs in Slovenia, and the perceived problems experienced by users, Int J Drug Policy, vol.27, pp.65-73, 2016.

D. Deimel, H. Stover, and S. Hosselbarth, Drug use and health behaviour among German men who have sex with men: results of a qualitative, multi-centre study, Harm Reduct J, vol.13, p.36, 2016.

T. Salway, D. Gesink, and S. Ibrahim, Evidence of multiple mediating pathways in associations between constructs of stigma and self-reported suicide attempts in a cross-sectional study of gay and bisexual men, Arch Sex Behav, 2017.

R. Giorgetti, A. Tagliabracci, and F. Schifano, Chems" meet sex: a rising phenomenon called "ChemSex, Curr Neuropharmacol, vol.15, pp.762-770, 2017.

K. Race, T. Lea, and D. Murphy, The future of drugs: recreational drug use and sexual health among gay and other men who have sex with men, Sex Health, vol.14, pp.42-50, 2016.

A. Gourlay, J. Fox, and M. Gafos, A qualitative study exploring the social and environmental context of recently acquired HIV infection among men who have sex with men in South-East England, BMJ, vol.7, p.16494, 2017.

S. Darke, Self-report among injecting drug users: a review, Drug Alcohol Depend, vol.51, pp.267-258, 1998.

:. Meyer, C. Capitant, . Charreau, . Netzer, . Leturque et al., Rezo Canada: D Thompson. The Canadian HIV Trials Network, APPENDIX 1. The ANRS-IPERGAY Study Team Includes the authors of this report and the following: INSERM SC10US19