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Advanced Neurology POTS with tics versus tic-like behaviors

subjects with functional tic-like behaviors compared to on functional tic-like behaviors from an international
those with neurodevelopmental tics. 34 registry reported high comorbidity rates with anxiety
It has been observed that functional movement (66%), depression (28%), autism spectrum disorder (ASD)
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disorders are characterized by inconsistency and (24%), and ADHD (23%); similarly, a single-center
distractibility – clinical features that play an important study that involved 105 patients reported even higher
role in differentiating them from organic movement rates of comorbid anxiety (70%) and affective disorders
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disorders. However, neurodevelopmental tics are often (40%). The identification of predisposing, precipitating
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intermittent and distractible: 27,39 diagnostic agreement and perpetuating factors (biopsychosocial model) plays
between experts can be suboptimal when based on clinical a key role in the clinical management of the different
phenomenology alone, as showed in a recent study. In manifestations of functional neurological disorder.
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general, functional tic-like behaviors become significantly The striking increase in functional tic-like behaviors
more pronounced in social settings compared to when since the COVID-19 outbreak offered a privileged
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the person is alone; in addition to situation-specific opportunity to further explore the possible association
manifestations, the presence of coprophenomena at between POTS and functional neurological disorder.
onset, interference with the person’s ability to carry out Specifically, little is known about the possible link between
intended actions or communication, episodes of intense POTS and different types of tic disorders, including
tic-like behaviors (“tic attacks”), and higher severity of the newly described phenotype of functional tic-like
the clinical presentation at initial diagnosis suggest a behaviors. We therefore set out to conduct an original
diagnosis of functional tic-like behaviors rather than study aimed at assessing the prevalence and clinical
neurodevelopmental tics. 41 correlates of POTS in two large clinical samples: patients
Members of the European Society for the Study of with neurodevelopmental tics who received a diagnosis of
Tourette Syndrome (ESSTS) have proposed a set of GTS, and patients who developed tic-like behaviors and
diagnostic criteria for functional tic-like behaviors. The received a diagnosis of functional tics since the onset of the
following three main criteria were suggested: (1) age at COVID-19 pandemic.
onset of at least 12 years, (2) rapid evolution of symptoms, 2. Methods
and (3) presence of at least four out of nine specific clinical
features (multiple types of tic-like behaviors, with a higher We conducted a retrospective chart review of two large
frequency of complex tics than simple ones; inconsistent clinical datasets from the specialist GTS Clinic, Department
tics that are not repetitive or stereotyped; complex of Neuropsychiatry, National Centre for Mental Health,
motor tic-like behaviors including context-dependent Birmingham, United Kingdom: (1) a clinical sample of
or violent/offensive tics; evolution of tics not following 694 consecutive patients with GTS assessed between July
the rostrocaudal progression; coprolalia; tics likely to 2008 and December 2024, and (2) a clinical sample of 233
be influenced by popular culture or social interactions; consecutive patients who presented with tic-like behaviors
frequent fluctuations in intensity and frequency and received a diagnosis of functional tics since the onset of
throughout the day; new tics emerging regularly). The the COVID-19 pandemic (April 2020 – December 2024).
same group of experts also proposed two minor criteria: Each patient was assessed by a behavioral neurologist
(1) comorbidity with anxiety/affective disorders, and with over 20 years of clinical experience with both primary
(2) other functional neurological symptoms. It has to be tic disorders and functional neurological disorders (AEC).
noted that the phenomenon of functional overlay might Comprehensive demographic and clinical data were
not be rare: in a large case series, around 40% of patients systematically collected to confirm the diagnosis of either
presenting with functional tics had a previous diagnosis GTS (neurodevelopmental tics) or functional neurological
of GTS. 36 disorder (functional tics) according to DSM-5 criteria.
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Little is known about the etiological and The assessment was based on the National Hospital
pathophysiological mechanisms of this relatively under- Interview Schedule for Tourette Syndrome, a detailed
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researched clinical phenotype. It has been hypothesized semi-structured interview schedule originally validated
that the psychological repercussions of the COVID-19 in patients with neurodevelopmental tics and adapted
pandemic, along with the lifestyle changes it brought about, for use in patients with functional tics by including
may have contributed to the striking increase in functional key items relevant to functional movement disorders.
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tic-like behaviors. Several studies showed that the most Specifically, we collected the following demographic and
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common comorbidities of functional tic-like behaviors clinical data: gender, age at assessment, age and modality
are anxiety and depression: for example, multicenter data of onset, environmental/psychological triggers and

Volume 4 Issue 2 (2025) 103 doi: 10.36922/an.8525