Is MDMA Neurotoxic to Humans? | ALPS Forum 2023 - Nicole Friedli

Based on animal studies demonstrating that 3,4-Methylenedioxymethamphetamine (MDMA) has neurotoxic properties, many have been speculating whether MDMA may also be neurotoxic to humans. For example, studies in rodents and non-human primates have shown MDMA-induced axonal degeneration, which has been presumed to occur in humans as well. However, findings from animal studies may not necessarily apply to humans, and studies investigating white matter changes in MDMA users are scarce, inconclusive, and affected by methodological constraints. In 2019 at the Psychiatric University Hospital Zurich, we started recruiting chronic recreational MDMA users and drug-naïve controls for a comprehensive study on the long-term effects of chronic recreational MDMA use. Our goal was to compare the two groups regarding their cognition, behaviour, and a variety of neurobiological markers. As part of our study, we conducted MRI scans on 39 MDMA users and 39 controls. The scanning protocol included diffusion-tensor imaging (DTI), which allows to investigate white matter alterations. By utilising a deep-learning approach to compare white matter between drug-naïve controls and MDMA users, we did not find any evidence of severe white matter lesions in MDMA users. Nevertheless, a few questions regarding the results remain unanswered, which is partly due to methodological limitations. At ALPS, we aim to bring together several outstanding researchers and clinicians working with psychedelic substances. Its purpose is to promote the latest scientific and clinical knowledge on the subject and discuss about key issues of the domain.