New research published in Biological Psychiatry indicates that enhancing myelination may help maintain the therapeutic effects of psychedelic-assisted treatments for post-traumatic stress disorder (PTSD). The study, released by Elsevier, suggests that changes in myelin—the insulating layer around neurons—could play a key role in sustaining improvements seen after treatment with drugs such as psilocybin and MDMA.
Psilocybin and MDMA have shown rapid clinical effects in patients with PTSD. However, lasting benefits depend on stabilizing brain circuits. The mechanisms behind these long-term effects are not fully understood. This new study identifies myelin as a potential link between the short-term psychedelic experience and longer-lasting neural network changes.
The research team used a rat model of contextual fear conditioning to test repeated low doses of psilocybin or MDMA. They measured anxiety-like behaviors, exploration, spatial learning, and memory. Results showed reduced anxiety-like behaviors alongside changes in oligodendrocyte biology—cells responsible for producing myelin—and genetic markers indicating myelin remodeling in the dentate gyrus region of the hippocampus.
Using advanced microscopy and genetic analysis, researchers confirmed that both psilocybin and MDMA promote physical repair of myelin. Blocking serotonin receptor 5-HT2A prevented both behavioral improvements and changes related to myelin. In contrast, using anisomycin to block fear memory formation reduced anxiety but did not repair myelin, suggesting structural recovery requires more than just memory suppression.
John Krystal, MD, Editor of Biological Psychiatry, stated: "The focus of psychedelic and MDMA research has been the effects of these drugs on neurons and neuroplasticity. This work has largely ignored a potentially important role for other cell types in the neurobiology of their therapeutic effects. Oligodendrocytes play a number of roles in the brain, which produce the myelin that insulates neurons. Subgroups of oligodendrocytes take up glutamate and contribute to glutamate homeostasis, protecting the brain from neurotoxicity. Another group of oligodendrocytes is involved in immune and inflammatory functions in the brain."
Dr. Bostancıklıoğlu commented: "Taken together, this moves oligodendrocytes and adaptive myelination from 'background correlates' to a mechanistically testable gate on the durability of psychedelic-associated circuit change."
Krystal added: "The implication of oligodendrocytes in the therapeutic effects of psychedelics and MDMA is important because of their many functions in the brain, including myelin formation, glutamate homeostasis, and neuroinflammation. The dependency of the therapeutic effects of these drugs in animals may suggest that myelin compromise may undermine their efficacy." He continued: "Overall, these data suggest that psychedelics and MDMA, like selective serotonin reuptake inhibitors (SSRIs) and ketamine, may promote the recovery from stress-related damage to myelin, contributing to clinical recovery."
The study also observed that psilocybin and MDMA reduce astrocyte reactivity associated with inflammation.
Researchers noted that enhancing myelination would not replace psychotherapy but could help support healthier communication among brain networks after an acute psychedelic session.
Dr. Bostancıklıoğlu concluded: "We often talk about psychedelics as 'opening a window' for brain plasticity. Recent work emphasizes that these drugs can acutely loosen entrenched network patterns and then leave a sub-acute period in which experience can reshape circuits. What we show here is that myelin-producing cells may be an underappreciated part of that story - helping translate a transient window into longer-lasting circuit change, at least in a fear-based rat model."
