{
  "abstract": "Background Chemsex, defined as the use of psychoactive substances to enhance sexual activity, is increasingly reported among GBMSM. In annual surveys conducted within the same PrEP cohort in Milan, chemsex prevalence among PrEP users was 16% in 2024 and 21% in 2025. This study aimed to estimate current chemsex prevalence, compare trends over 3 years, and explore patients’ feelings, needs, and preferred chemsex-related support within PrEP services.Methods Between January and February 2026, an anonymous online questionnaire was administered at 1 hospital-based and 1 community-based PrEP services in Milan. Data collected included demographics, sexual behaviors, substance use, and chemsex practices over the previous 12 months. Problematic substance use was assessed using the ASSIST score. Additional items explored perceived impact of chemsex and preferred support strategies.Results 394 PrEP users participated; 95% were cisgender men, and 99% identified as GBMSM. Median age was 45 years (IQR 32 – 47).Overall, 29% (115/394) reported substance use. The most frequently used substances were mephedrone (39%), MDMA (35%), cocaine (32%) and GHB/GBL (24%).Chemsex was reported by 18.5% (73/394), indicating a stable prevalence compared with previous years (16% in 2024; 21% in 2025). Among chemsex users, 41% described stable patterns compared with the previous year and 31% reported an increased use.Substance use during sex was reported as ‘always’ or ‘almost always’ by 19%, in ‘more than half of encounters’ by 25%, in ‘less than half’ by 25%, and ‘rarely’ by 31%.Concurrent alcohol use was reported by 40%, and 24% experienced chemsex-related adverse effects. 20% sought for specialist support.According to ASSIST scores, 27% were classified as low risk and 73% at moderate risk; no participants met criteria for high-risk use.The perceptions of PrEP users regarding their chemsex practices, and how these impacted their sex, personal and daily lives, were investigated: figure 1 shows the statements made and the responses given by users.Overall, 91% of respondents believed that PrEP services should address chemsex-related risk reduction and problematic use. Among chemsex users, preferred support modalities included counselling with trained healthcare professionals (60%), peer support (44%), online information (27%), and dedicated mobile applications (23%).Conclusions Chemsex remains consistently prevalent among PrEP users over 3 consecutive years. Although no high-risk substance use was identified, the high proportion of moderate-risk users, alcohol co-use, and reported adverse effects indicate unmet prevention needs within PrEP care. The strong user-driven demand for integrated, face-to-face support highlights an opportunity to embed structured chemsex risk-reduction interventions into routine PrEP services. Scaling provider training and peer-based approaches may enhance early interventions and improve sexual and mental health outcomes.Abstract P88 Figure 1",
  "authors": [
    {
      "affiliations": [
        "Luigi Sacco University Hospital, ASST Fatebenefratelli Sacco, Milan, Italy"
      ],
      "name": "C Fusetti"
    },
    {
      "affiliations": [
        "Milano Checkpoint ETS, Milan, Italy"
      ],
      "name": "E Caruso"
    },
    {
      "affiliations": [
        "Luigi Sacco University Hospital, ASST Fatebenefratelli Sacco, Milan, Italy"
      ],
      "name": "S Lazzarin"
    },
    {
      "affiliations": [
        "Milano Checkpoint ETS, Milan, Italy"
      ],
      "name": "L Nekrasova"
    },
    {
      "affiliations": [
        "Luigi Sacco University Hospital, ASST Fatebenefratelli Sacco, Milan, Italy"
      ],
      "name": "F Caruso"
    },
    {
      "affiliations": [
        "Milano Checkpoint ETS, Milan, Italy"
      ],
      "name": "P Vinti"
    },
    {
      "affiliations": [
        "Luigi Sacco University Hospital, ASST Fatebenefratelli Sacco, Milan, Italy"
      ],
      "name": "V Iannone"
    },
    {
      "affiliations": [
        "Milano Checkpoint ETS, Milan, Italy"
      ],
      "name": "R Repossi"
    },
    {
      "affiliations": [
        "Luigi Sacco University Hospital, ASST Fatebenefratelli Sacco, Milan, Italy",
        "Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy"
      ],
      "name": "A Giacomelli"
    },
    {
      "affiliations": [
        "Milano Checkpoint ETS, Milan, Italy"
      ],
      "name": "N Frattini"
    },
    {
      "affiliations": [
        "Luigi Sacco University Hospital, ASST Fatebenefratelli Sacco, Milan, Italy"
      ],
      "name": "M V Cossu"
    },
    {
      "affiliations": [
        "Milano Checkpoint ETS, Milan, Italy"
      ],
      "name": "M Cernuschi"
    },
    {
      "affiliations": [
        "Luigi Sacco University Hospital, ASST Fatebenefratelli Sacco, Milan, Italy",
        "Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy"
      ],
      "name": "A Gori"
    },
    {
      "affiliations": [
        "Luigi Sacco University Hospital, ASST Fatebenefratelli Sacco, Milan, Italy",
        "Milano Checkpoint ETS, Milan, Italy"
      ],
      "name": "D Moschese"
    }
  ],
  "title": "P88 Three-year trends in chemsex among PrEP clients and user-identified needs to inform integrated risk-reduction services",
  "uid": "e19ea6f4-3e14-5b78-9ba9-e726ed27b1ba"
}