Substance this website use, especially in the context of sexual activity, should be taken into account when developing new prevention and intervention programmes aimed at reducing sexual risk behaviour in HIV-infected MSM currently in specialized care. The prevalence and incidence of HIV infection in men who have sex with men (MSM) are persistently high in some Western countries. Therefore, it is of importance to identify determinants of risky sexual behaviour in this group. Sexual risk behaviour, defined as unprotected receptive or insertive anal
intercourse among HIV-positive MSM, was investigated in several studies. A meta-analysis of 30 studies on sexual risk behaviour among HIV-positive MSM found a prevalence of 43% for any unprotected anal intercourse. Prevalence was 30% for unprotected anal intercourse with seroconcordant sexual partners, 16% with partners of unknown HIV serostatus, and 13% with serodiscordant partners (multiple answers were permitted) . HIV-positive MSM report significantly more unprotected sexual intercourse
 and more receptive anal intercourse than HIV-negative MSM . Sexual risk behaviour increased after the introduction of highly active antiretroviral therapy (HAART) in the middle of the 1990s [4, 5] for casual, but not for steady partners [5, 6]. The consumption of psychoactive substances has been suggested to be an important factor influencing sexual risk behaviour [7, 8]. Sirolimus cell line Compared with the general population, MSM are a group with an increased prevalence of substance use and substance-related disorders. A meta-analytic review of studies on psychiatric disorders among MSM showed that MSM had a 1.51-fold higher risk for the 12-month
prevalence of alcohol abuse and a 2.4-fold higher risk for illicit drug abuse, according to the criteria of the DSM-IV (fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association), than heterosexual people . Population-based surveys also showed that MSM consumed illicit drugs more often than heterosexual men [10-12]. Several studies showed significant differences between MSM and heterosexual men regarding the consumption of illicit drugs [12-14], but (-)-p-Bromotetramisole Oxalate no or small differences for alcohol use [15-18]. In particular, there is a high lifetime prevalence of recreational club drug use in the gay community, especially in the context of parties. Cocaine, methamphetamine and MDMA (3,4-methylenedioxy-n-methylamphetamin, ‘Ecstasy’) were found to be most commonly used, followed by ketamine and γ-hydroxybutyrate (GHB) [19-21]. In addition, consumption of alcohol is associated with sexual risk behaviour in MSM. In a cohort study, heavy alcohol use and alcohol in the context of sexual activities were independent predictors of HIV seroconversion. People who drank heavily were significantly more likely [odds ratio (OR) 1.97] to become infected .