And is the stress of the pandemic playing a part?
Since the start of the pandemic, doctors in numerous countries — United States, Australia, Canada, United Kingdom — are reporting an increase in patients asking about jerking physical movements and vocal outbursts known as "tics," according to The Wall Street Journal.
The outlet reported that there seemed to be a common thread: Most of the young people had watched content from popular TikTok creators who say they have Tourette syndrome, one type of tic disorder.
These popular TikTok'ers film themselves and their tics — involuntary cursing, slapping themselves, making clapping sounds — and rack up millions of views. Videos hashtagged #tourettes have been viewed on the app more than 5 billion times.
Are TikTok Videos Causing Tics in Viewers?
Can watching videos of tics actually cause tics in the viewer? While the answer is not black and white, experts agree that most tic-causing conditions like Tourette syndrome have genetic predispositions, and certain stressors may trigger tics. You can also develop tics and not have Tourette syndrome.
There are other conditions that cause tics, like echopraxia, for example, which is "the involuntary imitation of the movements of another person." Another similar tic is called "echolalia," which is the repetition of phrases and noises that have been heard.
Dr. Mariam Hull, a neurologist and pediatric movements disorders specialist at Texas Children's Hospital has been studying if and how functional tics are spread through consuming media.
In a small study, Hull looked at six teenage girls ages 13-16 years — with no family history or childhood history of tics — who were all making similar noises and sounds and had similar tics. The researchers found that social media "may contribute to the spread of functional neurological symptom disorder, in a way previously requiring physical proximity."
Hull suggests it could be a combination of pandemic stress and growing teenage brains creating "conversion disorder," where the girls were subconsciously converting stress into physical symptoms. Conversion disorder is defined as "a mental condition in which a person has blindness, paralysis, or other nervous system (neurologic) symptoms that cannot be explained by medical evaluation."
Has Anything Like This Happened Before?
About 10 years ago, a similar mass illness event
occurred in upstate New York. A group of 18 high school girls in the small town of LeRoy made national news when they seemingly developed acute motor and vocal tics at once. After experts ruled out possible environmental causes, the diagnosis was conversion disorder.
Earlier this year, researchers in Germany published a paper describing an outbreak of tic-like behaviors among German teens, linked to a popular YouTube creator with Tourette syndrome. In the paper, the researchers coined the phrase "mass social media-induced illness."
The Link Between Social Media and Tics
some experts have suggested these teens could be anxious or depressed and are navigating the pandemic by seeking connection through mimicry. Other experts note that correlation does not equal causation, and that more studies are needed, including a much larger and broader peer-reviewed study that can show a direct link between social media and tics.
"We don't know why this is happening," Hull says. "My colleagues at Texas Children's are looking into what's really making these girls susceptible, and we are hoping to have answers soon."
Representatives at TikTok told The Dr. Oz Show they are proud that people living with Tourette's have found a home on TikTok "where they can fight stigma, find community, and express themselves authentically."
TikTok reps also say that the app has tools to help parents and teens "create the experience that's best for them," including using the "not interested" option, which will hide future videos of the same sound, and the "TikTok Family Pairing" feature, which let's a parent or guardian "link their TikTok account to their teen's to enable a variety of content and privacy settings, including Restricted Mode."
Users can also impose screen time limits and TikTok also periodically surfaces videos reminding viewers to take a break, the company says.