A new study from the Washington University School of Medicine in St. Louis shows how psilocybin, the psychedelic compound in magic mushrooms, affects the brain. The study found that a single dose of psilocybin, which causes changes in how we perceive space and time, can have lasting therapeutic effects. These effects include helping with mental illnesses like depression and PTSD.
“There’s a big effect at first, and when it’s gone, a small effect remains,” said Dr. Nico U. F. Dosenbach, one of the study’s senior authors. “This is what you want to see in a potential medicine.”
“We know a lot about the psychological and molecular effects of psilocybin,” said Dr. Joshua S. Siegel, the study’s first author. “But we don’t know much about what happens at the level of brain networks.”
Psilocybin caused big but temporary changes in the brain’s functional networks, especially the default mode network. After the drug’s effects wore off, small changes in the brain’s activity remained for weeks.
Dr. Siegel explained that psilocybin takes a system that’s key to thinking about the self in relation to the world and desynchronizes it temporarily. In the short term, this creates a psychedelic experience. In the long term, it makes the brain more flexible and able to enter a healthier state.
Participants rated their feelings of transcendence, connectedness, and awe during the experience. These ratings matched changes in brain networks.
“We got very precise data on the effects of the drug in each person,” said Dr. Ginger E. Nicol, another senior author. “This is a step toward precision clinical trials.”
Dr. Nicol explained that in psychiatry, we often don’t know who should get a particular medicine and how much they should get. By using this approach, we can find out who benefits from the medicine and make better use of it.
However, the researchers warn against self-medicating with psilocybin. It is not FDA-approved and can be risky without professional supervision.
The study found that changes in brain activity are linked to shifts in certain brain signals during psilocybin exposure. This phenomenon is shared by other psychedelics and engages the brain’s plasticity mechanisms, which help it adapt to new patterns of activity.
