\citet{36380888} review charts of 198 patients with tic-like phenomena and propose diagnostic criteria to separate those with typical tics, those with clinically diagnosed functional tics (FT), and those with a past typical presentation complicated by a fulminant worsening. "Only the presence of rostrocaudal progression and increased obsessive-compulsive behaviors were significantly different between patients with new-onset FT and those with functional worsening of a previous tic disorder. Results also showed that age at tic onset was not a contributing factor for group differentiation. Many patients with FT were not exposed to videos depicting tics on social media."
\citet{Fremer_2022} examined 32 patients with functional tic-like behavior with symptoms reflecting those on social media, including both operationalized psychiatric diagnosis and a psychodynamic focus. Symptoms typically started abruptly at the mean age of 19 years and were gradually deteriorating. In all patients, timely-related psychological stressors, unconscious intrapsychic conflicts, and/or structural deficits were identified. Nearly all patients (94%) suffered from further psychiatric symptoms. The authors concluded that pre-existing abnormalities in social behavior and psychiatric symptoms, but also GTS in combination with timely-related psychological stressors, unconscious intrapsychic conflicts, and structural deficits predispose to development of these symptoms.
\cite{Zea2022a} evaluated tic phenomenology in videos posted on TikTok. Most videos showed coprophenomena, often with unusual characteristics. Frequently, videos depicted aggression, throwing objects, self-injurious behaviors and repetition of long phrases. These videos were later assessed by independent blinded tic experts who concluded that GTS potrayals on highly viewed TikTok videos are not representative or typical for GTS.
\cite{Han2022} reported the prevalence and clinical characteristics of children with functional tic-like behaviors detected during the COVID-19 pandemic based on the analysis from the single center. There was a significant increase in the percentage of of functional tic-like behaviors in 2020 and 2021. In line with other studies, main differences between patients with functional tics characterized by several distinguishing features: predominance of females, later age of onset and higher rates of anxiety and depression. Patients with FTB also characterized with more frequent presence of coprolalia-like behaviors, complex phrases, self-injurious behaviors, higher rates of hospitalizations and school absenteeism.
\cite{Howlett2022} investigated the prognosis of functional tic-like behaviors in 20 adolescents and 9 adults. Overall, the authors have shown in this prospective study that adolescents have a better prognosis than adults with this diagnosis. As the most effective therapeutic approach treatment of comorbidities with SSRI and CBT was proposed.
Group of experts gathered by the Tourette Association of America \cite{Malaty2022} summarized their recommendations regarding the diagnosis of FTB:
Epidemiology
Several studies have addressed the prevalence and incidence of Tourette syndrome and chronic tic disorders. A systematic review and meta-analysis showed a global prevalence of TS of 0.5-0.6% and of 0.7% in the population of children and adolescents \cite{Jafari2022}.\citet{Tinker2022}, from the CDC, estimates that "350,000–450,000 U.S. children and adults have Tourette syndrome," while about a million have other chronic tic disorders.
In Asia, the National Taiwan Insurance Research Database was used to estimate incidence and prevalence of TS and chronic tic disorders from 2007-2015 \cite{Chou2022}. An increase in annual incidence rates was seen during this period in childhood and adolescence, and a decrease in adulthood. Furthermore, an increase in prevalence of TS and chronic tic disorders was seen.
In China, prevalence of tic disorders in school students between 6 and 16 years was shown to be 1.37% \cite{Yan2022}. There was seen a high comorbidity between TS and OCD.
Using 2016-2017 National Survey of Children´s Health data on children and adolescents between 6 and 17 years, parents reported that 0.3% of the children ever had been diagnosed with TS \cite{Charania2022}.