Chemsex, HIV, and Psychiatric Diagnosis in Gay or Bisexual Men in Hong Kong.

: Psychotropic substance use, for chemsex in particular, is common in gay or bisexual men (GBM) with HIV infection. This case-control study examined the association between Axis I psychiatric disorders and active psychotropic substance use, and identified factors affecting the prevalence of psychiatric disorders in HIV-infected GBM. : Participants were 62 HIV-infected self-identified GBM who reported psychotropic substance use in the past 1 year (cases), and 55 HIV-infected self-identified GBM without psychotropic substance use in the past 1 year and had negative toxicology tests at recruitment (controls). The Chinese-bilingual Structured Clinical Interview for DSM-IV (Axis I, Patient version) was followed to establish the psychiatric diagnoses. Socio-demographic data, level of social support, HIV-related data, and pattern of psychotropic substance use were collected. : Cases had lower level of social support, more depressive disorders (AOR 3.4, 95% CI 1.3-8.7, p=0.01) and psychotic disorders (AOR 7.2, 95% CI 1.2-41, p=0.03) but not anxiety disorders. Significant difference in the prevalence of psychiatric disorders was only evident for disorders with onset after HIV diagnosis. Methamphetamine dependence, weekly methamphetamine use for 2 years or more, using methamphetamine beyond chemsex, duration of HIV diagnosis were significant predictors for psychiatric disorders in the cases. : Active psychotropic substance use in HIV-infected gay or bisexual men was associated with an overall 3-fold increase in Axis I psychiatric disorders. Coordinated efforts from HIV, psychiatric and substance use services are needed to prevent harms arising from chemsex and to identify those in need and facilitate treatment access.