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Excerpt:
“Stop that! It’s not Tourette’s but a new type of mass sociogenic illness” - this was the title of an article published in BRAIN in August 2021 which received much public interest with a total of 108,647 views as of June 14th 2025. What prompted this commentary? Beginning in 2019, the incidence of adolescents and adults presenting for medical attention with impairing, dramatic, functional tic-like behaviors (FTLB) dramatically increased. As this increase reached global proportions during the COVID-19 pandemic and lockdowns, experts in Tourette Syndrome (TS) and FTLB realized this “outbreak” was a distinct clinical entity that could be confused with chronic tic disorders such as TS. FTLB is not TS, although some individuals may have both conditions FTLB is best conceptualized as a subtype of functional neurological disorder (FND). Subsequent actions by international academic collaborations, individual physicians, and advocacy groups contributed to a better clinical understanding of this disorder and formulation of diagnostic criteria Important factors that helped to raise awareness about this rapidly expanding clinical presentation of FTLB were international collaborations and efforts which provided physicians with assistance in making accurate diagnoses and providing appropriate treatments.
TS is defined as a chronic, childhood-onset disorder with combined motor and vocal tics lasting for at least a year. On average, tics start at the age of five to seven years, most typically with mild simple motor tics such as eye blinking and grimacing, followed by simple vocal tics such as sniffling and coughing, typically about two years later. Tics typically wax and wane and reach their maximum at age 10 to 12 years.
FND usually presents to clinicians as “disease mimics”. For example, individuals may manifest symptoms that resemble seizures, dissociative episodes, paralysis or weakness, tremor, or tics. Prior to 2019, FND presenting as TS was considered a very rare phenotype of FND that primarily presented with movements and sounds that overlapped more closely with standard clinical presentations of TS. Since 2019, however, individuals with FND mimicking TS presented much more commonly with predominantly complex movements and vocalizations such as obscene and socially unaccepted words, phrases and gestures, throwing objects, self-injurious behaviors, and long verbal phrases . The term FTLB has come into wider use as a result of this phenomenon.
In 2023, an international group of Tourette experts, including many of the authors of this commentary, established diagnostic criteria for FTLB based on a Delphi consensus that outlined supportive factors for the diagnosis of FTLB and the differential diagnosis of TS . They proposed that a clinically definite diagnosis of FTLB can be confirmed by an age at first symptom onset of 12 years or older, rapid onset and evolution of symptoms, and at least four of nine further phenomenological features as outlined in Table 2. Although there are clear “positive signs” for the diagnosis of FTLB, a better description of this patient group is needed to exclude circular reasoning due to a lack of clinical benchmarks.
Linked to the rise in FTLBs were two popular influencers, a young German man, who created the YouTube channel “Gewitter im Kopf” (eng. “Thunderstorm in the brain”) and a young English woman, who used the name “This Trippy Hippie” on TikTok. During the COVID-19 pandemic, these videos attracted tens of millions of views. In studies from several different countries and across continents, it could be clearly demonstrated that these presentations on social media directly influenced not only onset, but also clinical presentation of FTLB. In particular, according to an international database including 294 patients from ten tertiary referral centers for tic disorders from eight countries (Canada, United Kingdom, Germany, Australia, United States, Italy, Hungary, and France), FTLB was mainly seen in young female patients with mean age of 15 years (median 14 years; range, 8– 53 years), a demographic profile quite different from TS. In fact, there is about a 4:1 predominance ratio of the male sex in TS, while FND, including FTLB, is mainly seen in females. Furthermore, an overlap could be demonstrated in the type of movements (mainly complex arm and hand movements, head banging and tapping) and vocalizations (often with a large number of swear words, whistles, insults, and comments) as well as socially inappropriate behaviors (including spilling drinks, hitting, and throwing food and objects) between social media influencers and patients. Even more, depending on the place of residence and language of the patient, differences between clinical pattern and sex distribution were found, suggesting that exposure to particular social media content influences clinical presentation.. In this context, it is also important to mention that, while such behaviors are completely atypical for TS, mass use of social media easily creates misconceptions about TS.
TS is defined as a chronic, childhood-onset disorder with combined motor and vocal tics lasting for at least a year. On average, tics start at the age of five to seven years, most typically with mild simple motor tics such as eye blinking and grimacing, followed by simple vocal tics such as sniffling and coughing, typically about two years later. Tics typically wax and wane and reach their maximum at age 10 to 12 years.
FND usually presents to clinicians as “disease mimics”. For example, individuals may manifest symptoms that resemble seizures, dissociative episodes, paralysis or weakness, tremor, or tics. Prior to 2019, FND presenting as TS was considered a very rare phenotype of FND that primarily presented with movements and sounds that overlapped more closely with standard clinical presentations of TS. Since 2019, however, individuals with FND mimicking TS presented much more commonly with predominantly complex movements and vocalizations such as obscene and socially unaccepted words, phrases and gestures, throwing objects, self-injurious behaviors, and long verbal phrases . The term FTLB has come into wider use as a result of this phenomenon.
In 2023, an international group of Tourette experts, including many of the authors of this commentary, established diagnostic criteria for FTLB based on a Delphi consensus that outlined supportive factors for the diagnosis of FTLB and the differential diagnosis of TS . They proposed that a clinically definite diagnosis of FTLB can be confirmed by an age at first symptom onset of 12 years or older, rapid onset and evolution of symptoms, and at least four of nine further phenomenological features as outlined in Table 2. Although there are clear “positive signs” for the diagnosis of FTLB, a better description of this patient group is needed to exclude circular reasoning due to a lack of clinical benchmarks.
Linked to the rise in FTLBs were two popular influencers, a young German man, who created the YouTube channel “Gewitter im Kopf” (eng. “Thunderstorm in the brain”) and a young English woman, who used the name “This Trippy Hippie” on TikTok. During the COVID-19 pandemic, these videos attracted tens of millions of views. In studies from several different countries and across continents, it could be clearly demonstrated that these presentations on social media directly influenced not only onset, but also clinical presentation of FTLB. In particular, according to an international database including 294 patients from ten tertiary referral centers for tic disorders from eight countries (Canada, United Kingdom, Germany, Australia, United States, Italy, Hungary, and France), FTLB was mainly seen in young female patients with mean age of 15 years (median 14 years; range, 8– 53 years), a demographic profile quite different from TS. In fact, there is about a 4:1 predominance ratio of the male sex in TS, while FND, including FTLB, is mainly seen in females. Furthermore, an overlap could be demonstrated in the type of movements (mainly complex arm and hand movements, head banging and tapping) and vocalizations (often with a large number of swear words, whistles, insults, and comments) as well as socially inappropriate behaviors (including spilling drinks, hitting, and throwing food and objects) between social media influencers and patients. Even more, depending on the place of residence and language of the patient, differences between clinical pattern and sex distribution were found, suggesting that exposure to particular social media content influences clinical presentation.. In this context, it is also important to mention that, while such behaviors are completely atypical for TS, mass use of social media easily creates misconceptions about TS.