Single Psilocybin Dose Reverses Pain And Depression In Mice Within 24 Hours
Scientists test psilocybin fungi in a laboratory. (Photo by 24K production on Shutterstock)
In a word
- One dose, weeks of relief: A single psilocybin injection reversed both chronic pain and depression type symptoms in mice within 24 hours, with effects at least 12 days.
- Brain circuits, no injuries: Pain relief came from soothing hyperactive neurons in a region of mood transformation and brain paine, not healing of real injuries, which remained visible at the end of the study.
- The location counts: Psilocybin worked when it has reached the anterior cingular cortex of the brain but had no effect when injected near the spinal cord, showing pain relief in the brain.
- A soft balance beats the brute force: The partial activation of the psilocybin of two serotonin receptors has been simultaneously proven to be more effective than to fully activate a single or block pain signals.
- Pain and depression are intertwined: Mice with worse pain have constantly shown a worst anxiety and depression, and psilocybin relieved both simultaneously by rebalancing the same cerebral circuits.
Philadelphia – Researchers from the University of Pennsylvania have found that a single treatment with psilocybin, the active compound of magic fungi, quickly reversed chronic pain and symptoms of depression in mice. The relief lasted at least 12 days, the duration of the observation after treatment.
The study, published in Nature neuroscienceConfirms what doctors have observed for a long time but had trouble treating: chronic pain does not only injure the body. He reclassified the brain, creating a psychological suffering which worsens the original pain.
Chronic pain breaks brain thermostat
The research team created two types of lasting pain in mice during the four -week study. Some have undergone nerve damage. Others had serious inflammation in their legs. The two groups have become hypersensitive to touch and developed what looked like mice versions of anxiety and deep depression. They avoided open spaces, abandoned more quickly in swimming tests and have shown coordination of altered movements.
Brain imaging revealed the culprit. A region called the anterior cingular cortex, which deals with both the emotional experience of pain and regulates mood, had essentially broken. Think about it as a smoke detector that will not stop going up even after the end of the fire. The nerve cells in this area drew 40% more than they should have been, and they would not calm down.
Press the reset switch
DAY 27, the researchers gave mice a single psilocybin injection. Within 24 hours, pain sensitivity dropped at normal levels in both groups. The mice also returned to typical behavior in tests measuring anxiety and depression.
Improvements lasted. Even 12 days after the unique treatment (at the end of the experience), pain relief continued and the mood remained stable.
The location of the action of psilocybin mattered enormously. When the researchers injected psilocin (which psilocybin becomes in the body) directly in the anterior cingular cortex, they saw spectacular improvements. When they injected him into the spinal cord near the injury site, nothing has changed. The activity levels that had been 40% above normal fell to the base line in a few minutes.
Why did it work
Psilocybin affects two types of serotonin receptors in the brain: 5-HT2A and 5-HT1A. The researchers found that he must both work his magic.
When the researchers blocked one or the other before giving psilocybin, all the advantages have disappeared. The pain has returned, anxiety has remained high, behaviors similar to depression have persisted.
But to outpatate these same receptors individually did not help either. The maximum of 5-HT2A receivers Only only increased activity in already hyperactive circuits. The maximum of 5-HT1A receptors has decreased the activity alone, but has only provided a modest relief of pain and no mood advantage.
Only partial activation by the psilocybin of the two receivers has simultaneously restored normal brain activity. Rather than blocking pain signals or damaging all brain activity, psilocybin recalibbs specific circuits that chronic pain has unbalanced.
Pain and depression: a double -meaning street
The study has mapped how chronic pain and depression are reinforced. Mice with one or the other type of chronic pain showed almost identical patterns: a worst pain was correlated with more depression and anxiety, measured through multiple behavioral tests.
When the researchers examined individual animals, the severity of pain coherently predicts psychological distress. Males and female mice showed the same relationship.
In an experience, the mice could choose between two pieces: one where they had already received psilocybin, and one where they had obtained salt water. They spent much more time in the psilocybine room. The researchers say that it shows that the mice have associated this space to feel better, not that they were looking for the drug itself.
The relief of pain did not come from healing itself. When the researchers examined the sites of nerve lesions 40 days later, nervous tangles were still present. The reversal of pain has come entirely of changes in the brain.
What it means for people
Of course, while the study used mouse models, keep in mind that human chronic pain implies additional psychological and social complexity. The specific dose, the delivery method and the treatment calendar would require in -depth tests for human use.
For the 50 million Americans living with chronic pain, as well as the large part that also fight on depression and anxiety, research offers a new understanding of how these conditions intertwine in the brain. If similar effects occur in humans, periodic treatment could one day become possible, but this is not proven.
The first human trials with psilocybin for chronic pain are already underway, although they remain exploratory. The question of whether the dramatic effects observed in mice will result in human patients is uncertain, but neurobiological ideas alone make understanding understanding of how chronic pain transforms the brain and why it resists treatment.
Non-liability clause: This article sums up preclinical research and is for information purposes only. It does not provide medical advice or does not approve of psilocybins to use approved search parameters outside.
Paper summary
Methodology
Researchers have induced chronic pain in adult mice using two established models: a spared nervous lesion (surgical cut of two of the three branches of the sciatic nerve) and an adjuvant injection of complete freund (large-volume inflammatory compound in the foot carrier). They measured the mechanical sensitivity using von Frey electronic tests, which records the precise pressure from which the mice remove their paws. Anxiety and depression type behaviors have been assessed by higher labyrinth, forced swimming test, tail suspension test, open field test and clear / dark box tests. Calcium imaging with two photons in awakened mice and fixed to the head expressing Gcamp6F allowed real -time visualization of neural activity in the anterior cingular cortex. For drug experiences, researchers have used systemic psilocybin injections (0.5 mg / kg) as well as local psilocin applications, serotonin and antagonist receptors. The size of the samples varied from 5 to 30 mice per group depending on the experience.
Results
The two pain models have produced mechanical hypersensitivity lasting 27 days, the withdrawal thresholds falling at less than 50% of normal. Increased depression and anxious behavior coincided with pain. A single dose of psilocybin on day 27 reversed mechanical allodynia within 24 hours, by returning sensitivity to pre-bar levels, with persistent effects until day 40. Helpted behaviors normalized in a similar way. The two -photon imaging revealed that chronic pain increases spontaneous neuronal activity in the anterior cingular cortex by around 40%, and the local psilocin application reduced hyperactivity to the reference base in a few minutes. Bilateral injection of psilocin to the anterior cingular cortex replied The effects of systemic psilocybin on pain and mood, while vertebral injection has had no effect. The blocking of 5-HT2A or 5-HT1A receptors before psilocybine completely prevented the therapeutic effects. Complete agonism to these individually or combined receptors has only produced partial advantages compared to the partial agonist activity of psilocybin.
Boundaries
The study was conducted exclusively in rodent models, which may not fully grasp the complex nature of chronic human pain. All pain models have been acutely induced rather than developing naturally. The relatively short monitoring period (40 days) does not know if the services would persist in the long term or if a repeated dose may be necessary. Sex -based analysis was preliminary, some behavioral tests showing small sample sizes to detect potential gender differences. The mechanism by which psilocybin induces lasting changes beyond its immediate effects remains uncertain. The study did not examine potential adverse effects or security problems beyond basic behavioral observation. Local experiences of drug administration required surgical procedures that could themselves influence pain treatment.
Financing and disclosure
This work was supported by the National Institutes of Health (R35GM151160-01) and the ASRA chronic medicine research grant awarded to JC Psilocybin was granted by the Usona Institute. The authors have not declared any competing interest.
Details of the publication
Hammo, A., Wisser, S. & Cichon, J. “Psilocybin at single dose quickly and permanently relieves allodynia and anxoopressive behavior in chronic pain mouse models.” Nature neuroscienceOctober 2, 2025. DOI: 10.1038 / S41593-025-02068-0
