Plastic Fantastic? One dose of psilocybin could cause changes in your brain.

Given the global prevalence of MDD (Major Depressive Disorder) it is no surprise that scientists are interested in anything that might help. Of course, there are a lot of medications which can make a positive difference but recently attention has turned to the serotonin agonist psilocybin (pronounced as sil-o-cy-bin). Early evidence from human trials suggests that this compound can have significant and long lasting positive effects for those with mild to moderate MDD. Now a new study might shed some light on how this happens.

Lyons et al (2026) demonstrated that one 25mg dose of psilocybin is enough to cause structural changes in the brain as well as the improvement in mood and thinking that has been shown in earlier studies. Whilst it is too early to say exactly what these changes are, it seems likely that one or more neuroplastic process are 're-wiring' important neural networks in the brain and this is turn helps people think more clearly and feel more positive.

This research remains controversial, not least because psilocybin also causes significant short term hallucinations, so much so that many protocols for trials include an 8 hour wait in a clinical setting to make sure the patients are ok to leave without supervision.

Is this a new way forward in the fight against a depression? Only time, (and some good experimental work) will establish causality and responsibility with the certainty needed for widespread use in the community.

Think about this ...

There is a lot of interest in any new treatment for MDD, partly because of the prevalence of the disorder within many populations. Is it responsible for the media highlight experimental new treatments like this? Are there some treatments we shouldn't explore? Why? Why not? Would you be happy for someone you care about to take part in a trial for an experimental treatment like psilocybin (or the use of ketamine for treatment resistant depresssion (TRD)?)

Further Reading

Lyons, T., Spriggs, M., Kerkelä, L. et al. Human brain changes after first psilocybin use. Nat Commun 17, 3977 (2026). https://doi.org/10.1038/s41467-026-71962-3