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NCT Number: NCT07512869

Host Led Harm Reduction Approach Among Men Who Have Sex With Men Who Engaged in Chemsex in Bangkok, Thailand: A Pre-Implementation Study

This study evaluates the pre-implementation phase of a host-led harm reduction model for men who have sex with men (MSM) engaging in chemsex in Bangkok, Thailand, focusing on understanding harms, contexts, and needs to develop a tailored intervention.

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Key information

Conditions

HIV Prevention Behavior Chemically-Induced Disorders Chemsex Communicable Diseases Disease Attributes Genital Diseases Harm Reduction Infections Mental Disorders Mental Health Pathologic Processes Pathological Conditions, Signs and Symptoms Personal Satisfaction Psychological Well-Being Sexual Behavior Sexually Transmitted Diseases Sexually Transmitted Infections (STIs) Substance Use Substance-Related Disorders Urogenital Diseases

Age range

18 year and older

Sex eligibility

Male

Study type

Observational

Primary location

About this study

HAMMOCK is a cross-sectional mixed-methods study designed to explore chemsex practices among MSM, including both hosts and guests, as well as key stakeholders such as CSOs, hospital staff, and police.

The study aims to:

  • Explore substance-related, sexual health, mental health, and socio-legal harms
  • Understand the context and dynamics of private chemsex parties
  • Co-develop a novel host-led harm reduction model
  • Identify barriers and facilitators to implementation The study includes both quantitative (self-administered questionnaires) and qualitative (in-depth interviews) components and follows a two-phase approach: exploration and preparation phases under the EPIS framework.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • MSM aged ≥18 years
  • Able to communicate in Thai
  • Specific by group:
  • Chemsex hosts: hosted ≥2 times in past 6 months
  • Chemsex guests: attended ≥2 times in past 6 months
  • CSO / hospital / police staff: working ≥3 months in related roles
  • Provide informed consent

Exclusion criteria

  • Unable to provide informed consent (e.g., under substance influence at consent)

Treatment and study plan

Self-administered questionnaire assessment

Behavioral

Participants (chemsex party hosts and guests) will complete structured self-administered questionnaires to assess:

  • Substance use patterns and related harms
  • Sexual health risks (e.g., condom use, HIV/STI testing, PrEP/ART adherence)
  • Mental health status using validated tools:
  • Patient Health Questionnaire-9 (PHQ-9)
  • Generalized Anxiety Disorder-7 (GAD-7)
  • Socio-legal harms including stigma and discrimination

Semi-structured in-depth interviews (IDIs)

Behavioral

All stakeholders will participate in semi-structured in-depth interviews:

  • Exploration phase: guided by EPIS framework
  • Preparation phase: guided by
  • Theoretical Domains Framework (TDF) (hosts & guests)
  • Consolidated Framework for Implementation Research (CFIR) (organizational stakeholders)

The interviews aim to:

  • Identify harms associated with chemsex
  • Explore current practices and contexts
  • Identify barriers and facilitators
  • Inform development and refinement of a harm reduction model

Development and refinement of harm reduction model

Behavioral

A novel four-pronged harm reduction model will be developed and refined based on quantitative and qualitative findings.

Domains include:

  • Substance use harm reduction
  • Sexual health harm reduction
  • Mental health harm reduction
  • Socio-legal harm reduction

Primary outcomes

  1. Substance use-related harm assessed by self-administered questionnaire

    Time frame: Baseline (during Exploration phase, prior to model development)

    Substance-related harms will be assessed using a structured self-administered questionnaire. The assessment includes:

    • Patterns of substance use (snorting, injecting, ingesting, anal insertion)
    • Frequency of use
    • Physical harms (e.g., injection-related injuries, overdose)
    • Psychological harms (e.g., substance dependence) This is a descriptive assessment; no composite scale score is generated.

  2. Sexual health risk behaviors assessed by self-administered questionnaire

    Time frame: Baseline (during Exploration phase, prior to model development)

    Sexual health risks will be assessed using a structured questionnaire including:

    • Number of sexual partners
    • Condom use
    • HIV/STI testing history
    • Self-reported HIV status
    • Pre-exposure prophylaxis (PrEP) use and adherence
    • Antiretroviral therapy (ART) adherence among participants living with HIV This is a descriptive assessment; no composite scale score is generated.

  3. Depression severity assessed by Patient Health Questionnaire-9 (PHQ-9)

    Time frame: Baseline (during Exploration phase, prior to model development)

    Depression will be assessed using the Patient Health Questionnaire-9 (PHQ-9):

    • Score range: 0 to 27
    • Interpretation:
    • 0-4: Minimal depression
    • 5-9: Mild
    • 10-14: Moderate
    • 15-19: Moderately severe
    • 20-27: Severe Higher scores indicate worse depression severity

  4. Anxiety severity assessed by Generalized Anxiety Disorder-7 (GAD-7)

    Time frame: Baseline (during Exploration phase, prior to model development)

    Anxiety will be measured using the Generalized Anxiety Disorder-7 (GAD-7):

    • Score range: 0 to 21
    • Interpretation:
    • 0-4: Minimal
    • 5-9: Mild
    • 10-14: Moderate
    • 15-21: Severe Higher scores indicate worse anxiety

Secondary outcomes

  1. Perceived stigma and socio-legal harm assessed by structured questionnaire

    Time frame: Baseline (during Exploration phase, prior to model development)

    Socio-legal harms will be assessed using a structured questionnaire adapted from the CLYMAX study, including:

    • Internalized stigma related to chemsex
    • Perceived discrimination (family, workplace, social)
    • Legal risks and experiences This is a descriptive assessment; no composite scale score is generated.

Study contacts

Contact information is provided by the study sponsor or research team.

Jakkrapatara Boonruang, MD

CONTACT

[email protected]

6689 965 7862

Nittaya Phanuphak, MD,PhD.

CONTACT

[email protected]

6681 825 3544

Sponsors and collaborators

Lead sponsor

Institute of HIV Research and Innovation Foundation, Thailand

Other

Collaborators

  • International AIDS Society

Registry information

Acronym: HAMMOCK

Important dates

Study start
2025
Primary completion
2027
Study completion
2028
First posted
Apr 6, 2026
Registry last updated
Apr 6, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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