Scientists at UC San Francisco and Imperial College London have found that the drug psilocybin can help depressed people by freeing them up from long-held patterns of self-focus.
The discovery points towards a general mechanism through which the brain may be acting therapeutically on the brain to alleviate depression and possibly other psychiatric conditions that are marked by fixed patterns of thinking.
Scientists analyzed fMRI brain scans from people who had participated in trials. In the first one, all the participants had treatment-resistant depression and knew they were being given a drug. In the second one, the participants were not told if they had been given a placebo or a drug that turned out to be escitalopram, an anti-depressant. All the participants received the same type of therapy.
The scans showed that the treatment reduced connections within brain areas that are connected tightly in depression, including the default mode, salience, and executive networks, and increased connections to other regions of the brain that had not been well integrated.
The cognitive functioning of participants got better. The study ended three weeks after the second dose of psilocybin because of the changes to the brain. The brains of those who received escitalopram did not show any changes similar to those of those who did not.
Serotonins like ayahuasca can affect brain networks that become active in depression. One hypothesis is that the drugs temporarily disrupt these connections and give them a chance to reform in new ways.
In previous studies we had seen a similar effect in the brain when people were scanned while on a drug, but here we are seeing it weeks after treatment for depression, which suggests a carry-over of the acute drug action.
We don't know how long the changes in brain activity seen with psilocybin therapy last, and we need to do more research to understand this.
The authors caution that patients with depression shouldn't self-medicate with the drug. The trials took place under controlled conditions, using a regulated dose in a laboratory, and involved extensive psychological support before, during, and after the trial.
The study points to a mechanism that may explain how the drug helps to alleviate depression and other mental illnesses.
David Nutt, head of the Imperial Centre for Psychedelic Research, said that the brain was more flexible and fluid with the use of the drug.
The full list of authors and funding can be found in the paper.
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The materials were provided by the University of California. Laura Kurtzman wrote the original. Content can be edited for style and length.
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