The Thrills and Spills of GHB: Patterns and Negative Events Connected with Use in a Large Community Sample.

Introduction: Gamma-hydroxybutyric acid (GHB) and its precursor gamma-butyrolactone (GBL) are psychoactive substances commonly associated with men who have sex with men (MSM) and sexualized substance use contexts. Large-scale studies exploring broader sociodemographic characteristics and substance use behaviors among GHB/GBL users remain scarce. Methods: A convenience sample was recruited online through nightlife contexts to complete an anonymous online-questionnaire with a one-year follow-up. The survey assessed sociodemographic data, use of GHB/GBL and other psychoactive substances, GHB/GBL-related adverse events, and lifetime psychiatric diagnosis. Participants were categorized as occasional or frequent users based on the past 12 months. Results: Among 2196 participants, 47.4% reported GHB/GBL use within the past year; among these, 72.9% were occasional users (< 1x/week), and 27.1% frequent users (≥ 1x/week). At one-year follow-up, 10.9% of the sample was retained. The majority of users were male, with 40% of frequent users and 42% of occasional users identifying as homosexual. Frequent users reported more negative events associated with use (e.g., unconsciousness and overdose) and screened more often for problematic use (CAGE-AID). GHB/GBL use frequency was positively associated with methamphetamine, research chemical, and benzodiazepine use, and negatively associated with alcohol use. Conclusions: This study provides insight into GHB use in a diverse sample and confirms higher levels of adverse effects and problematic use patterns among frequent users. Findings highlight the need for prevention and harm reduction strategies that go beyond MSM/chemsex contexts. Broader, inclusive public health approaches are essential to reduce risks and address the evolving landscape of GHB use.