Psychedelic drugs have the ability to reopen "critical periods" in the brain, during which mammals are highly receptive to acquiring new skills and knowledge, according to new research.
The study, published in the science journal Nature on 16 June, found that psychedelics such as ibogaine, ketamine, LSD, MDMA and psilocybin could make the brain more conducive to learning new skills and healing.
For years, scientists have been searching for methods to unlock critical periods in the brain, during which mammals exhibit heightened sensitivity to environmental stimuli. These developmental periods have previously been associated with significant learning processes in various species, including birds learning to sing and humans acquiring new languages or relearning motor skills after suffering a stroke.
The recent study, led by researchers from Johns Hopkins University in the United States, sheds light on the connection between psychedelic drugs and the reopening of social reward learning critical periods.
“There is a window of time when the mammalian brain is far more susceptible and open to learning from the environment. This window will close at some point, and then, the brain becomes much less open to new learning," study co-author Dr Gül Dölen said.
Dr Dölen, an associate professor of Neuroscience at the Johns Hopkins University School of Medicine, has previously investigated the effects of MDMA on octopuses.
The Nature study discovered that psychedelic substances share a common ability to unlock these pivotal developmental stages in the brain, which could potentially pave the way for innovative approaches to stroke recovery and open doors to treating a broader range of conditions.
According to the study, the implications of these findings extend far beyond the known benefits of psychedelics in treating conditions such as depression, addiction and post-traumatic stress disorder (PTSD). The researchers believe that these drugs hold immense potential for treating an even wider range of ailments, including stroke, autism, deafness and blindness.
Earlier research had shown that MDMA, an empathogenic psychedelic known for its ability to evoke feelings of love and sociability, could trigger the opening of critical periods in mice.
Scientists had previously attributed MDMA's prosocial properties as the driving force behind its effect on critical periods. However, the latest study revealed that other psychedelic drugs, lacking MDMA's sociability-inducing properties, could also reopen these crucial developmental windows. Whereas cocaine does not reopen the social reward learning critical period.
The scientists examined the effects of five different psychedelic drugs — ibogaine, ketamine, LSD, MDMA, and psilocybin — on the reopening of critical periods.
To assess the impact of these drugs on learning abilities, the researchers conducted a behavioural test on adult male mice. The experiment involved training the mice to associate a specific environment with social interaction and another environment with isolation. After administering the psychedelic drugs to the mice, the researchers observed the amount of time the mice spent in each environment.
The experiment demonstrated that the critical period opened in adult mice treated with ketamine for 48 hours. Psilocybin, on the other hand, extended this state for two weeks. When using MDMA, LSD and ibogaine, the critical period remained open for two, three and four weeks respectively.
The study found that the duration of the acute subjective effects of psychedelics is consistent with the duration of the open state induced by each drug.
“The open state of the critical period may be an opportunity for a post-treatment integration period to maintain the learning state,” Dr Dölen said. “Too often, after having a procedure or treatment, people go back to their chaotic, busy lives that can be overwhelming. Clinicians may want to consider the time period after a psychedelic drug dose as a time to heal and learn, much like we do for open heart surgery.”
These findings hold significant implications for the future of psychedelic implementation in clinical practice and the development of novel treatments for mental illness. Researchers believe that harnessing the potential of psychedelics to reopen critical periods could revolutionise the way we approach stroke recovery and potentially transform the treatment landscape for numerous other conditions.
As the scientific community delves deeper into the intricacies of the brain's development and the remarkable effects of psychedelic drugs, new doors are opening towards a future where these substances could play a pivotal role in healing and recovery.