Study Reveals Psilocybin's Long-Lasting Effects on the Brain and Potential for Treating Depression

The psychedelic compound psilocybin, found in magic mushrooms, is known for inducing a mind-altering experience that can last for several hours. However, a new study has found that its influence on the brain can persist for weeks, shedding light on why psilocybin can distort the sense of space, time, and self, and its potential therapeutic benefits for severe depression.

Dr. Joshua Siegel, a co-author of the study from Washington University School of Medicine in St. Louis, explains that the findings could also benefit companies developing novel psychedelics and similar non-hallucinogenic drugs. “It could help to determine if a novel drug is hitting the right targets and to decide what is the optimal dose,” he said.

Published in the journal Nature, the study involved a randomized control trial with seven healthy participants, each of whom had previously used psychedelics. Participants were given either a 25mg dose of psilocybin or 40mg of methylphenidate (generic Ritalin) and underwent multiple MRI scans before, during, and after the administration of each drug.

The study revealed that psilocybin, unlike methylphenidate, caused a disruption in the default mode network (DMN) of the brain. The DMN is an interconnected group of brain regions active when the mind is wandering and not focused on a particular task.

This network is crucial for creating a sense of self and is linked to the perception of space and time. Siegel noted that the disruption of this network could explain the extraordinary experiences reported during psilocybin trips.

While most brain activity returned to normal within a day, a notable reduction in communication between the DMN and the anterior hippocampus—a brain region critical for memory and the perception of space and time—persisted for three weeks. This sustained effect may help explain why people often report increased flexibility in their self-perception and their relationship to their environment after taking psilocybin.

This plasticity in the brain is believed to underpin the success of psychedelic-based treatments for conditions like treatment-resistant depression. By making the brain more receptive to therapy, psilocybin can facilitate profound changes in mental health.

Despite the demanding nature of the research, Siegel noted a strong interest from volunteers wanting to participate in studies on psychedelics. “We didn’t have trouble finding participants,” he said.

The study provides crucial insights into the prolonged effects of psilocybin on the brain, offering a potential explanation for its therapeutic benefits. As the understanding of these mechanisms grows, it could pave the way for more effective treatments for severe depression and other mental health conditions.

Do you believe psilocybin should be more widely studied and used in mental health treatments?