Researchers from the University of Liverpool have examined how ecstasy (MDMA) affects different regions of the human brain.
Dr Carl Roberts and Dr Andrew Jones of the University of Liverpool’s Institute of Psychology, Health and Society, together with Dr Catharine Montgomery of Liverpool John Moores University, carried out a systematic meta-analysis of molecular imaging studies to assess the neurobiological effects of regular ecstasy use. Their review combined data from seven independent studies that used molecular imaging techniques to measure serotonin transporter availability across multiple brain regions in people who regularly used ecstasy compared with matched control participants.
Previous individual studies have produced mixed results when comparing cognitive and emotional function in ecstasy users and non-users. This meta-analysis aimed to synthesise available imaging data to clarify whether ecstasy use is associated with long-lasting alterations in the serotonin system that could underlie observed cognitive or mood changes.
Impacting emotional reactions
Ecstasy is known to primarily affect the serotonin system. Serotonin is a neurotransmitter produced in specialised neurons and plays a central role in regulating mood, emotion, anxiety, sleep, appetite, aggression, memory, and perception. By focusing on serotonin transporters (SERT)—the proteins responsible for clearing serotonin from the synaptic space—the analysis assessed how transporter availability differs between ecstasy users and controls and how those differences might influence brain function.
The pooled results indicate that ecstasy users exhibited significant reductions in serotonin transporter availability across many cortical and limbic regions. Reduced SERT levels can alter serotonin signalling and are likely to affect how individuals process and regulate emotional responses to environmental stimuli. Such changes are consistent with reports of mood disturbances and altered emotional reactivity among some long-term ecstasy users.
Psychobiological changes
Dr Roberts explained that the analysis included data from 157 ecstasy users and 148 control participants across 14 brain regions. Eleven of those 14 regions showed statistically significant reductions in serotonin transporter availability among ecstasy users compared with controls. The greatest reductions were observed in neocortical and limbic areas, with the occipital cortex demonstrating one of the largest effect sizes.
In contrast, subcortical structures such as the caudate, putamen and midbrain did not show significant group differences in this pooled data. This regional pattern aligns with preclinical findings suggesting that serotonin axons with the longest projections from the raphe nuclei may be particularly vulnerable to MDMA-related changes.
The authors note that while the biological findings are robust across the pooled imaging studies, clinical interpretations remain cautious. It is plausible that reduced serotonin transporter availability contributes to mood alterations and other psychobiological changes described in some MDMA users. These neurobiological changes could also help explain cognitive deficits reported in behavioural studies of ecstasy use, although direct causal links require further longitudinal and mechanistic investigation.
Polydrug use is a complicating factor in much of the literature: many individuals who use ecstasy also use other substances, making it difficult to isolate the effects of MDMA alone. The meta-analysis attempted to account for these differences by including studies with polydrug-using controls when appropriate, but heterogeneity across studies remains an important consideration.
Publication: The meta-analysis is titled “Meta-analysis of molecular imaging of serotonin transporters in ecstasy/polydrug users” and was published in the journal Neuroscience and Biobehavioral Reviews. The article lists Carl Alexander Roberts, Andrew Jones, and Catharine Montgomery as authors and was published online on February 6, 2016 (doi: 10.1016/j.neubiorev.2016.02.003).
Data and scope: Seven imaging studies, 157 ecstasy users, 148 controls, analysis across 14 brain regions. Main pooled effect suggests ecstasy-related SERT reductions (standardised mean difference ~0.52), with significant regional variation and the largest effects in cortical regions such as the occipital cortex.
Conclusions and next steps: The analysis supports the conclusion that regular ecstasy use is associated with reduced serotonin transporter availability in multiple cortical and limbic brain regions. These findings provide a biological basis for further research into how long-term or heavy MDMA exposure may influence mood regulation, emotional processing, and cognitive function. Future work should aim to clarify causality, the time course of recovery (if any), and the specific contributions of concurrent use of other substances.
Source: University of Liverpool press materials and the authors’ published meta-analysis.
Abstract (summary)
The meta-analysis compared SERT measures in ecstasy users and polydrug-using controls across 14 brain regions. From seven studies including 157 ecstasy users and 148 controls, the main effect indicated reduced serotonin transporter availability associated with ecstasy/MDMA use. Significant reductions were present in 11 of the 14 regions analysed, particularly across neocortical and limbic areas, while no consistent group differences were found in several subcortical regions. The pattern of effects is consistent with preclinical evidence that serotonin axons with the longest projections are most susceptible to MDMA-related changes.