Summary: Researchers report that regular use of the club drug GHB (gamma‑hydroxybutyrate), and especially repeated GHB‑induced comas, are linked to changes in brain networks involved in long‑term memory and working memory, and to higher levels of stress and anxiety.
Source: European College of Neuropsychopharmacology
Regular recreational use of GHB and repeated GHB‑induced comas are associated with measurable changes in cognition and brain function, including impairments in long‑term and working memory, lower measured IQ scores, and increased stress and anxiety. These findings were presented at the ECNP congress in Barcelona.
GHB (gamma‑hydroxybutyrate), sometimes called “G” or “liquid ecstasy,” is a central nervous system depressant commonly used in nightlife settings and private parties. It can produce short‑lived euphoria but also causes sedation that can quickly progress to loss of consciousness or coma. Among regular recreational users, repeated GHB‑induced comas are not uncommon; some individuals have experienced dozens of such episodes. In Europe, GHB overdose and coma account for a substantial share of drug‑related emergency medical visits, ranking behind heroin and cocaine and showing an upward trend.
To investigate how repeated GHB exposure and GHB‑related coma episodes affect the brain, researchers at Amsterdam UMC recruited three groups of 27 men each: (1) regular GHB users who had experienced multiple GHB‑induced comas (minimum four comas), (2) regular GHB users who had never lost consciousness from GHB, and (3) polydrug users who had used various drugs but never used GHB. All participants completed an adult reading test used as an estimate of IQ, completed questionnaires assessing anxiety, depression, and perceived stress, and performed several neurocognitive tasks while undergoing functional magnetic resonance imaging (fMRI).
The study produced two principal findings. First, even GHB users who had not experienced a coma showed altered recognition of negative emotional expressions compared with drug users who never used GHB, suggesting that GHB use alone may affect emotion processing. Second, participants who had experienced multiple GHB‑induced comas showed distinct cognitive and brain differences compared with both GHB users without coma history and polydrug users who had never used GHB. Specifically, those with multiple comas demonstrated lower scores on the reading‑based IQ proxy despite similar educational attainment, poorer performance on verbal long‑term memory and working memory tasks, and altered brain activation and connectivity in memory‑related networks observed on fMRI. Additional analyses indicated these differences were not explained by use of other drugs.
The investigators also report that participants with multiple GHB‑induced comas experienced substantially higher levels of perceived stress and anxiety—figures cited in preliminary materials indicate approximately 63% more stress and 23% more anxiety in this group. Functional MRI data showed altered activity in regions and networks involved in memory, and reduced connectivity between pathways that support verbal long‑term memory and working memory. Taken together, these findings suggest that repeated episodes of GHB‑induced unconsciousness are associated with measurable brain and cognitive changes.
Lead researcher Filipa Raposo Pereira commented that little is known about GHB’s effects on the human brain and that this study represents the first set of functional MRI data examining regular GHB use and multiple GHB‑induced comas. She emphasized that the results point to potential risks for regular recreational users, particularly those who experience repeated comas, who displayed cognitive differences compared with both non‑coma GHB users and non‑GHB polydrug users.
Professor David Nutt (Imperial College London) noted that these findings are of interest to recreational users and likely reflect periods of hypoxia in the brain related to excessive GHB concentrations. He added that medically supervised use of GHB—such as in the treatment of narcolepsy—appears not to carry the same risks, so patients receiving the drug under clinical supervision should not be alarmed by these findings.
Study limitations
The investigators caution about two important limitations. First, the study included only male volunteers, so results may not generalize to female GHB users. Second, the research is observational and demonstrates associations between GHB use, GHB‑induced comas, and brain or cognitive differences; the design does not establish causality. Longitudinal or interventional studies would be needed to confirm causal effects.
Funding: This work was supported by the Ministry of Health of the Netherlands.
Source: European College of Neuropsychopharmacology
Publisher: Organized by NeuroscienceNews.com
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Original Research Presentation: The study was presented at the 31st Congress of the European College of Neuropsychopharmacology.