A comprehensive analysis reveals that different psychedelic drugs have remarkably similar effects on brain networks. This research, published in Nature Medicine on April 6, identifies a distinct pattern of brain activity connected to five psychedelics, including psilocybin, LSD, and ayahuasca. The study aggregated findings from 11 brain-imaging studies, totaling over 500 brain scans from 267 individuals.
“What’s surprising is that even with the varying pharmacological properties of these substances, they share a common impact on the brain,” notes Danilo Bzdok, a neuroscientist and AI researcher at McGill University in Montreal. “It raises questions about our current classifications of these drugs.”
Shan Siddiqi, a psychiatric neuroscientist at Harvard, labels this as the largest study of its type to date. Most previous neuroimaging studies on psychedelics had limited participant counts, making this research a significant step in overcoming that issue.
Numerous clinical trials support the potential of psychedelics in treating conditions like depression, anxiety, and addiction. Bzdok emphasizes that understanding the brain’s response to these substances could influence future drug development, which holds promise for mental health treatment.
Psychedelic Experiences
Psychedelics shift perception and cognition temporarily, but the underlying neural mechanisms have been somewhat elusive.
Previous studies examining brain activity during psychedelic experiences have often been small and yielded mixed results. Bzdok refers to the scientific evidence as “fragmented and nascent,” pointing to the need for more comprehensive data.
To tackle these challenges, Bzdok and his team devised a method to merge various scans and analyze how activity in different brain areas fluctuates together over time. They utilized data sets from countries like the UK, Switzerland, the Netherlands, the US, and Brazil, focusing on the effects of substances such as psilocybin, LSD, mescaline, DMT, and ayahuasca.
Petros Petridis, a psychiatrist at New York University who studies psychedelics, explains that the prevailing theory posits that psychedelics, like psilocybin, disintegrate brain networks. However, Bzdok’s analysis indicates these drugs enhance communication between brain regions. In participants who used psychedelics, areas involved in higher-order cognitive functions were significantly more interconnected than in sober individuals.
Moreover, these neural networks showed stronger connections with areas responsible for processing visual and auditory information and those coordinating motor functions. There were also notable changes in brain activities among subcortical regions related to perception, motivation, and reward.
