Amazing: psychedelic and phantom limb pain


First part of a two-part series on psychedelics and chronic pain

The key is neuroplasticity: the ability of the brain to change and adapt (or, as they say in psychedelic circles, to reconnect) in such a way that negative or harmful thought patterns are broken and forged. new healthier paths.

This is the general mechanism by which scientists now believe that at least some of the benefits of psychedelics for a wide range of psychiatric disorders occur. And, just as they seem to help treat depression, addiction, post-traumatic stress disorder, obsessive-compulsive disorder, and other mental health conditions, psychedelic drugs are now being investigated as a remedy for a especially problematic chronic form. pain.

Neuroplasticity appears to play a central role in the published case study of a 35-year-old man, the intractable pain in the phantom limbs resulting from an amputated leg suddenly disappeared. The treatment? Three doses of psilocybin combined with visual mirror feedback. a form of therapy used to relieve amputated phantom-limb pain in which patients position a mirror in the center of the body and perform a motor task with a limb while observing its reflection, giving the illusion of movement of the body. missing limb.

Not just a lot of good vibes

The article describing this rapid recovery aided by psilocybin mushrooms was published in the journal Neurocase in May 2018 and co-author of the patient himself, Albert Lin, a researcher at the University of California at San Diego (UCSD) i National Geographic TV explorer and presenter. Four of Lin’s companions a UCSD, including neuroscientist Vilayanur Ramachandran, who pioneered mirror visual feedback in the early 1990s, also contributed to the article.

While they are certain that this combination of high doses of the psychedelic compound and the visual feedback from the mirror caused Lin to stop feeling sharp pain in his missing foot, the authors admit that they are not entirely sure how this happened. . One theory, and very plausible, is based on what we already know about how classical psychedelics work, those whose effectiveness focuses on the activation of the 5.HT2A serotonin receptor: literally helps the brain make new connections.

“It is possible that the psychoactive effects of psilocybin are accompanied by an increase in multimodal functional connection status and neuroplasticity through the serotonergic effect,” the authors speculate. “If that’s the case, psilocybin can make the brain more receptive to mirror therapy and make pain reduction last longer or even disappear.”

In other words, the drug and therapy seem to have worked together to reconnect Lin’s mind. The result saved the life of this “bionic Indie Jones” – who now sails, swims and hikes with the prosthetic leg – and illustrates the power of psilocybin and neuroplasticity. (Still, perhaps to avoid mentioning magic mushrooms, a profile of Lin a The San Diego Union-Tribune healed his healing to “a lot of good vibes.”)

A new clinical trial

Two years after the publication of Lin’s case report, another role from UCSD the researchers delved into the relationship between psychedelics and chronic pain. This was primarily a review article, with no new data, but brought together in one place all existing evidence in the scientific literature for the treatment of various forms of chronic pain with psychedelics, specifically psilocybin and LSD. In all, only eight papers appeared dating back to 1964.

Among these, two others treated phantom limb pain. The first, of 1967, contained more case studies. Five of six patients described in the paper achieved a significant and sustained reduction in phantom pain in the limbs after the use of LSD. The second, of 1977, described how five out of seven patients with phantom limb pain saw an improvement in pain and at least a 50% reduction in analgesic use after taking LSD.

Now, some of the authors of this review want to add to the test database using a new one clinical trial. Housed inside UCSD‘s Psychedelia and Health Research Institute – formed in 2016 after and inspired by Lin’s rehabilitation – the study will be the first randomized placebo-controlled clinical trial in humans to examine the safety and efficacy of treating chromatic pain in phantom limbs with psilocybin.

The research team expects to begin enrolling a total of 30 patients by the end of the summer. Half will receive a relatively large dose of psilocybin (25 mg) on ​​two occasions and the other half will see two doses of niacin, a placebo. The researchers will use MRI to look for brain changes after dosing, and then correlate these findings with measures of pain and psychological functioning assessed at subsequent clinical visits.

About 1.7 million people they live with limb losses each year in the United States, and the vast majority experience phantom limb sensations that begin in the days and weeks after amputation. For many, pain can be severe and difficult to treat with existing therapies. Undoubtedly, this was the case with Lin, who tested the opioids, cannabis, and the nerve pain medication Pregabalin before experimenting with psilocybin. While the new trial will not include visual feedback, its success could still point to a potentially deadly new option for millions of people suffering from this debilitating condition.

Restoration of the brain

“Of all the chronic pain conditions, phantom limb pain is one of the few that is almost a purely central phenomenon of pain,” said Joel Castellanos, a pain doctor at UCSD and sub-investigator of the trial, as well as lead author of the 2020 review. “The pain stems from a dissonance between the lack of nerve input within the area of ​​the brain that represents the area that is no longer there,” he said. dir Castellanos a Project CBD.

The way psilocybin can help “align the body representation of the brain” and therefore eliminate pain, is no different from how it can be used to treat anxiety, depression, eating disorders, and other problems. chronic neuropathics. or “diseases of the central nervous system,” Castellanos said.

“Our brain has these firing patterns that are maladaptive and pathological and, by using psychedelics as a reset button, it restores the fire’s ability to fire in a healthier and more efficient way,” he explained. “The longer the patients are in these pathological states, the firmer the neural pathways … [T]It is worth exploring further the idea that something can restore these paths. “

Nate Seltenrich, a freelance science journalist based in San Francisco Bay, covers a wide range of topics such as environmental health, neuroscience and pharmacology.

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