A new study appears to shed light on the vexing medical mystery of long COVID, with a reduction in serotonin levels in patients seen as a key component. If the research published in Cell holds true, it suggests that some people might be able to take medication to boost the neurotransmitter to mitigate symptoms such as brain fog, reports the New York Times. The study out of the University of Pennsylvania builds on previous research and lays out a chain of events, as explained in Medical Xpress. Remnants of the virus linger in a patient's gut, which triggers the immune system to release proteins called interferons to fight the infection. The interferons, however, lead to inflammation that hampers the body's ability to absorb an amino acid called tryptophan, which is vital to the production of serotonin.
"These effects can explain a wide spectrum of symptoms that our patients with long COVID have," study co-author Benjamin Abramoff tells STAT News. "It certainly points us in a direction of the underlying root causes." Reduced levels of serotonin could affect short-term memory and factor into other cognitive issues that many people with long COVID have.
One caveat is that the study was small, involving about 120 people in total, about half of whom were experiencing symptoms of long COVID. Future studies with a larger pool of people will aim to replicate the findings. The CDC estimates that one in 5 people who get regular COVID go on to have long COVID, and symptoms often vary from patient to patient. (More long COVID stories.)
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