New study finds psilocybin addresses strong inflammatory signals associated with Parkinson's Disease.

Psilocybin addresses strong inflammatory signals associated with Parkinson's.

Its impacts could likely help treat other diseases as well.

By Noah Daly

For years, researchers have been exploring how psychedelics can address inflammation. When psychedelics enter the brain, they clump onto serotonin receptors. This has made them such interesting candidates for treating mental health conditions, but what about physical illnesses?

Scientists have already been able to show that some psychedelics have powerful anti-inflammatory properties. An open-label study at Johns Hopkins published in February suggests that people living with post-treatment Lyme disease can find relief from symptoms related to inflammation. Early clinical studies on classic psychedelics—primarily psilocybin and LSD—suggest they can significantly reduce cluster headache attack frequency and break active cycles. Now, findings in a new paper from researchers at the University of California, San Francisco, and Columbia University show that those qualities could translate to treating inflammation in humans.

The purpose of their study was to show whether psilocybin could be a safe and effective therapeutic for people diagnosed with Parkinson's disease who also have depression. They also found some of the most consequential human data on how psychedelics impact inflammation yet collected, which they published in a new paper for the journal JAMA Psychiatry on Wednesday.

Inflammation is the body's response to physical damage, infections, and foreign objects invading the body, among other things. It's a cascade of processes designed to help the immune system handle the business of helping us feel better, but when there's no business to handle, inflammation can be deadly. For example, a runaway immune response like sepsis can cause widespread inflammation and contribute to organ failure. Severe allergic reactions can also trigger life-threatening complications, like airway swelling and dangerous drops in blood pressure. Inflammation can be harmful even when a real threat remains, as in an excessive response to infection. It can also persist after the original trigger has gone.

We're still not sure what triggers Parkinson's. It is a neurodegenerative disorder that attacks the nervous system. It's characterized by the progressive loss of motor control and is commonly associated with mood disorders. Several types of inflammation in the brain and in the immune system contribute to the progression of Parkinson's, and it's believed the gradual decay of neurons producing dopamine also plays a key role in the disease, which affects roughly 10 million people worldwide according to the Parkinson's Foundation.

Neurodegenerative disorders like this usually exclude someone from psychedelic therapy, but the original study gave researchers enough evidence that psilocybin is safe to use in Parkinson's patients and might even help them feel better. In this new publication, the researchers turn to five signaling molecules associated with inflammation. Participants first received 10 milligrams and, approximately two weeks later, 25 milligrams.

By analyzing blood samples from the participants, all of whom had both Parkinson disease and mood dysfunction, they were able to see how the levels of each of those five molecules changed before and after treatment.

The scientists found that inflammation decreased significantly after the participants received the drug and remained lower a month after the final dose. While the researchers noted that the study's small cohort of participants knew they were receiving psilocybin, and that there was no control group, they found an important proof-of-concept, according to D. Parker Kelley, a research scientist in the Mitochondrial PsychoBiology group at Columbia University who was a first author on the new paper.

"It's a potential jumping-off point for a lot more research in this area," Kelley told NPR. "That may apply not only to Parkinson's, but also neuropsychiatric disorders like depression and anxiety, and even cardio-metabolic and inflammatory disorders."

Future research will need to follow the thread that researchers like Charles Nichols, who's been studying the anti-inflammatory effects of psychedelics at LSU for the past several decades. In 2008, Nichols and his colleagues found that several psychedelics reduced inflammation in lab-grown cells. Since then, they've studied the effects of psychedelics on arthritis and heart disease among others in animal models, but the new data from UCSF and Columbia brings much-needed evidence that this translates to treating inflammation in people, too.

Before psilocybin can be considered an anti-inflammatory ready to use in humans, researchers still need to establish whether it directly reduces inflammatory markers, rather than changes in the things that move those markers like stress or other factors. Repeated blood samples would also help identify when changes begin and how long they last.