TORONTO -- A rise in teen girls developing 鈥渢ic-like鈥 behaviours could be linked to TikTok, along with an increase in anxiety and depression, resulting in symptoms similar to Tourette鈥檚 syndrome, doctors say.

In a study entitled 鈥,鈥 published in the August issue of the journal Movement Disorders, researchers said when they began interviewing patients, many reported that the behaviours began after watching videos on platforms like TikTok and YouTube 鈥渟howing persons allegedly having Tourette鈥檚 syndrome.鈥

鈥淗owever, many of these videos show movement and vocalizations not typically present in Tourette鈥檚 syndrome, including predominantly complex, variable and often continuous movements and elaborated and variable swearing and offensive phrases,鈥 the study鈥檚 authors wrote.

Researchers from pediatric hospitals around the world found that referrals for tic-like behaviours 鈥渆xperienced a dramatic increase鈥 during the pandemic, 鈥渁lmost exclusively鈥 in girls aged 12 to 25, according to the study.

Since March 2020, referrals in the Canada, the U.S., the U.K., Germany and Australia have reached 20 to 35 per cent from one to two per cent prior.

The study notes that the videos, which are posted by young people all over the world and have millions of views, but are not verified by experts, may 鈥渢rigger tic-like behaviours in susceptible individuals.鈥

The study used data from 290 registry participants from a Calgary tic disorder clinic that was collected between 2012 and June 30, 2021 to describe the symptoms and demographic characteristics of the youth affected in this global phenomenon.

When the data was analyzed, 270 patients were found to have a primary tic disorder and 20 patients were found to have rapid onset 鈥渇unctional tic-like behaviours鈥 or FTLBs.

Of the 20 patients with FTLBs, 17 had no history of previous tics, whereas three had mild simple tics earlier in childhood that were never detected.

The rapid onset of the FTLBs all occurred in all participants during the pandemic period (after March 1, 2020) and all endorsed exposure to influencers on social media, mainly TikTok, with tics or Tourette鈥檚 syndrome.

The patients with FTLBs exhibited symptoms ranging from repetition of random words such as 鈥渒nock knock,鈥 or repetition of curse words, or obscene, offensive or derogatory statements, the study said. Others had complex hand and arm movements like clapping, pointing or throwing objects, and some exhibited behaviour where they would hit or bang parts of their body, other people or objects.

Those with FTLBs were more likely to be female and have anxiety or a major depressive disorder diagnosis, but most have no definite history of previous tics. Those with FTLBs typically escalated in frequency and severity over a period of hours to days, prompting emergency room visits and even hospitalization, the study said.

The study notes that this phenomenon is a 鈥渘oticeable departure鈥 from the usual demographic and natural history of Tourette鈥檚 syndrome, which disproportionately affects boys with onset occurring between the ages four to seven.

鈥淕lobal availability and increased usage of social media, particularly during the coronavirus disease 2019 pandemic, coupled with great social interest in the stage of Tourette鈥檚 syndrome, might lead to maladaptive gains further intensifying symptoms in susceptible individuals,鈥 the study鈥檚 authors wrote.

Researchers posit that the pandemic has been a major source of stress and anxiety for people globally, resulting in increased mental health symptoms and demand for mental health services, with 鈥渋ncreased social isolation and widespread utilization of social media鈥 likely factors in a relevant portion of the patients reporting FTLBs.

鈥淓xternal factors like watching popular social media personalities' videos portraying tics or tic-like behaviours may have instilled a belief that 鈥榯ics鈥 may catalyze peer acceptance or even popularity,鈥 the study says. 鈥淭his exposure to tics or tic-like behaviors is a plausible trigger for the behavior.鈥

While social media exposure was reported in all of the patients with FTLBs at the Calgary clinic, that was not the case for every patient at the other global centres, which is why researchers are calling for a more in-depth study of the link between social media and the onset of symptoms and their severity in youth.