Psychobiome draws attention in studies
DEAR DOCTORS: Is it possible that all mental illness comes from a bad gut? Does that mean it would be possible to find a cure?
DEAR READER: As researchers explore how the trillions of microbes that live in our gastrointestinal tracts affect our health and well-being, the link between the gut and the central nervous system has grown increasingly clear.
The central nervous system, or CNS, consists of the brain and the spinal cord. In addition to overseeing movement and controlling the body’s response to sensory information, the CNS is the seat of thought, memory and emotion. Decades of studies have found a link between the composition of the gut microbiome and CNS functions such as mood, cognition and mental health. This connection has even been given its own name — the psychobiome.
A recent case study by scientists in Australia described their work with a patient living with bipolar disorder. This is a mental health condition marked by extreme mood swings, including emotional highs and intense lows. The patient, a 28-year-old man who was diagnosed with bipolar disorder when he was 15, underwent a fecal transplant. That’s a procedure that introduces the stool of a healthy person into the colon of someone who is ill. In the months following the procedure, the man experienced a marked lessening of his symptoms.
In a different case study, published by researchers from Switzerland, Iran and Germany, two women who had been living with severe depression for many years also received fecal transplant therapy. In the weeks after the procedure, each woman reported a decrease in her symptoms.
While the outcomes here are intriguing, it’s important to note that these are single-patient case studies. That means the results apply only to the specific situations described. They cannot be generalized for a larger population. Further research with more participants, and over longer periods of time, is needed to put these case studies into perspective.
It appears that the gutbrain connection plays an important role in neurological disorders, as well. These include multiple sclerosis, Parkinson’s disease, Alzheimer’s disease and amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease. Large-scale studies use stool samples to analyze the types and species of gut microbes in participants’ intestines. These have identified distinct differences between the microbial profiles of healthy individuals and those with mental health and neurological disorders. Whether these anomalies are the cause of the disorders or represent additional symptoms is not yet clear. However, the findings point to the possibility of using beneficial bacteria to treat mental health disorders, either with the microbes themselves, or with drugs that simulate their metabolic functions.
An upcoming clinical trial, approved by the Food and Drug Administration, will break ground by using that approach. Researchers plan to test two specific strains of live microorganisms to see if they will slow progression of symptoms in people living with Parkinson’s disease. If successful, it will mark an important new phase of research into the psychobiome.