Can Kids’ Gut Bacteria Lead to Tic Disorders?

Since its classification in the late 1800s, the scientific community has mostly studied the effects of Tourette Syndrome and other associated tic disorders, not the cause. Now a University of Miami research study is trying to change that.

Tourette Syndrome is the most extreme of a group of childhood-onset tic disorders characterized by involuntary physical tics, like repeated blinking, head, neck, and facial movements, and vocal tics, including coughing, sniffing, or uncontrollably blurting out words or phrases. Research into those disorders has historically focused on how to help patients limit and control their specific tics through behavioral exercises and medication. 

Barbara Coffey, M.D., chief of the Division of Child and Adolescent Psychiatry at the University of Miami Health System and chair of the Department of Psychiatry and Behavioral Sciences at the University of Miami Miller School of Medicine, believes it’s now time to focus instead on the causes of those neurodevelopmental disorders. 

With her team at the UHealth Tourette Center of Excellence, Dr. Coffey is launching a study to understand whether fungi and bacteria in people’s digestive systems increase inflammation in the brain, leading to various tic disorders.

“This is really cutting edge,” Dr. Coffey says. “This is what we need to do.” 

The “Microbiome Study,” which begins on December 1, is now recruiting volunteers ages 8 to 15. That is the age when tic disorders are most extreme. 

Dr. Coffey and her team will observe 40 children with tic disorders and 40 children without tic disorders. The participants will not receive any medication or undergo any medical procedures – they will simply be observed and submit blood, urine, and stool samples during three visits over two months. 

“It’s easy,” Dr. Coffey says. “The procedures aren’t going to take a long time, so we’re hoping we’ll be able to recruit very widely.”

If the study shows a clear link between inflammation in the gut and chronic tic disorders, Dr. Coffey says the research would expand to include more participants worldwide to ensure that the connection is widespread. 

From there, Dr. Coffey and other researchers could study new treatments to reduce tic-inducing inflammation, including antibiotics, anti-inflammatory treatments, or probiotics, a broad range of microorganisms made popular through dietary supplements.

But first, Dr. Coffey’s team must establish that the link exists. 

The idea of a person’s digestive tract influencing tic disorders was first raised in a Chinese study published in 2021. 

That small-scale study showed how Chinese children with high levels of certain bacteria in their gut suffered from tic disorders while children with lower levels of those bacteria did not. 

Dr. Coffey was fascinated by that idea and teamed up with Marco Bortolato, M.D., Ph.D., a professor at the University of Utah, to study it further in the United States. The duo won a grant from the National Institute of Neurological Disorders and Stroke (NINDS) to look for a particular protein – a cytokine called tumor necrosis factor α (TNF-Alpha) – in the microbiome of children and adolescents. Those proteins eventually make their way into the brain, leading to inflammation and possibly various tic disorders.

Dr. Coffey also wants to measure whether higher levels of those inflammation-causing proteins in the brain lead to more severe tics. 

“Our hypothesis is that the more inflammation they have, the more severe tics they have,” she says.

Dr. Coffey is encouraging volunteers throughout South Florida to sign up on their own. 

Learn more about the microbiome study and whether your child or adolescent may be able to participate.

Alan Gomez is a contributing writer for UHealth’s news service.

Tags: clinical trials, digestive health, Dr. Barbara Coffey, kids health, microbiome, tic disorders, tourette's