Brain Changes Following Psychedelic Experiences

A recent small study suggests that a single psychedelic experience can lead to physical alterations in the brain. These changes might explain why some individuals report psychological benefits from the experience.

The research, which appeared in Nature Communications, focused on psilocybin, the active compound in magic mushrooms. Previous studies have shown that this substance seems to alleviate symptoms of depression and anxiety. It has also shown potential in the realm of addiction treatment.

However, the exact mechanisms through which these benefits manifest remain uncertain.

This topic is garnering increasing scientific interest. Recently, measures were taken to expedite research into psilocybin and another psychedelic, ibogaine. In light of this, the FDA has fast-tracked reviews for two companies studying psilocybin for depression.

Researchers have divided into two primary schools of thought: one group believes that the psychedelic experiences themselves are crucial for the benefits and brain changes, while the other posits that the compounds alone, rather than the experiences, are key.

The new study leans towards the first perspective, indicating that the intensity of the psychedelic experience plays a significant role.

“The better people scored in terms of psychological insight, the more substantial their therapeutic improvements,” said Robin Carhart-Harris, the study’s senior author and a neurology professor at the University of California, San Francisco.

The study involved 28 individuals in London, averaging 41 years old, all of whom were novices to psychedelics and free from psychiatric diagnoses. Initially, they received a 1 mg dose of psilocybin, deemed too low to induce a trip, serving as a placebo. During this time, researchers monitored their brain activity. Participants underwent additional brain scans, including MRIs, over the next month.

After a month, they received a 25 mg dose, which aligns with the standard used in therapeutic settings. The psilocybin for this study was supplied by a company under expedited review with the FDA.

The researchers tracked brain activity at various intervals following the dose. Additionally, diffusion tensor imaging (DTI) was employed to observe water movement along neural fibers. Some changes detected in specific brain regions suggested possible lasting structural alterations.

“People often perceive this as a reorganization of neural pathways,” said Albert Garcia-Romeu from Johns Hopkins School of Medicine. “However, they’ve really identified changes in the way water flows along these fibers.”

Garcia-Romeu noted that while the study’s findings indicate structural changes post-exposure, not all may be beneficial—some resemble changes observed after traumatic brain injuries.

The study found that stronger trips correlated with more pronounced changes. Although participants on the placebo dose reported no trips, almost everyone experienced significant alterations in consciousness during the 25 mg dose. Those who reported deeper experiences—connected to greater brain activity—showed marked differences in water movement along brain pathways a month later.

“We aren’t entirely sure what this means, but the tracts appear to become denser,” Carhart-Harris mentioned, contrasting these findings with conditions like Alzheimer’s disease, where tracts tend to become less connected.

Notably, about 70% of participants experienced increased well-being after the psychedelic dose.

Dr. Joshua Siegel, a psychiatry professor at NYU Langone Health, emphasized that there seems to be a significant relationship between altered states of consciousness and a person’s ability to shift their thought patterns.

The notion is that psychedelic experiences may disrupt neural pathways, allowing for reorganization and breaking free from entrenched patterns, Carhart-Harris commented.

Scientists have become increasingly interested in how psychedelics may influence brain plasticity—the ability of the brain to reform neural connections. Some studies suggest psychedelics increase the synapses in brain regions associated with emotional regulation and depression, Siegel noted. Yet, much of this research has focused on rodents, raising questions about human applications.

While there’s agreement on the need for further studies to replicate findings and explore therapeutic implications, Garcia-Romeu highlighted the insights gained from this research.

“This contributes to our understanding of why these substances might have enduring effects on people,” he stated. Unlike other medications, where benefits typically diminish once the drug wears off, psychedelics seem to offer lasting changes in moods and anxiety.

“This research provides clearer guidelines for studying these effects in humans and understanding their therapeutic potential,” Garcia-Romeu concluded.