The COVID-19 pandemic and its impact on tic symptoms in children and young people: a prospective cohort study

The coronavirus (COVID-19) pandemic created a global health crisis resulting in the United Kingdom (UK) government implementing unprecedented societal restrictions from March 2020 to April 2021, including practicing social distancing, lockdown restrictions consisting of home confinement for all but essential activity and wearing of personal protective equipment (PPE) when outside the home. Furthermore, from March-May 2020, school closures were enforced for all but vulnerable children and children of keyworkers, affecting an estimated 80–90% of children [1]. Despite early concerns that these restrictions may exacerbate declining trends in children and young people’s (CYP) mental health in the UK, there is uncertainty as to the actual impact [2, 3], with few published studies examining CYP under 18-years [4] or CYP with existing mental health conditions.

The impact of COVID-19 is difficult to calculate being confounded by several key factors, including the evidence of existing decline in CYPs mental health pre-pandemic [2], restricted provision of some mental health services during the pandemic [4] and the lack of pre/post-pandemic measures in order to assess change. Thus, it is perhaps unsurprising that the existing evidence is heterogeneous [5].

Early findings indicated that lockdown was associated with poor mental health [6, 7]. Probable mental health conditions in the UK rose from 10.8% to 2017 to 16% in July 2020 [8], with respondents from lower socioeconomic groups reporting the greatest mental health deterioration [9]. One of the few studies with pre/post pandemic data (conducted outside the UK) indicated a moderate increase in depressive symptoms during lockdown [10]. However, UK based surveys showed that young people reported feeling happier during summer 2020 [11], with no change in anxiety, depression or well-being. Indeed, those who were struggling pre-lockdown made significant improvements in these three areas [5, 12].

Although during early lockdown, it was intuitively believed that young people with an existing mental health condition would be particularly vulnerable to the negative mental health impact of COVID-19 [13] and school closures [14], there was also evidence that some of this group benefited from being released from the complexities and stressors associated with school attendance [15]. However, to date, there have been limited studies into the impact of lockdown on children with specific mental health conditions and neurodevelopmental disorders. Amongst other conditions, the UK National Health Service (NHS) have identified young people with mental health conditions, including neurodevelopmental disorders (such as attention deficit hyperactivity disorder [ADHD] and autism spectrum disorder [ASD]) as being vulnerable to the negative impact of COVID-19 [13]. No evidence is available on these conditions, but research suggests young people with anxiety are more likely to have been significantly impacted [16]. Given the associated changes in routine, young people with ASD may also have been disproportionately affected, however, the available evidence is varied with some reporting improvement in symptoms and others deterioration [17].

Young people with tic disorders may be particularly affected by the pandemic. Tics are sudden, repeated, non-rhythmic motor or vocal movements. Tourette syndrome, a form of tic disorder, is often diagnosed if two or more motor tics (e.g., blinking and shoulder shrugging) and at least one vocal tic (e.g., clearing the throat) have been present for at least one year. The condition is highly comorbid with other neuropsychiatric disorders; 85% of young people with a tic disorder will also have obsessive-compulsive disorder, ADHD, depression, anxiety and/or ASD [18]. Statistics pre-pandemic suggest that Tourette syndrome and chronic tic disorders affect approximately 1% of young people and are associated with significant distress, impairment and reduced quality of life [19]. There are specific consequences of COVID-19 that are likely to impact on patients with tics, including pandemic-related anxiety, confinement, restrictions on physical exercise [20], or the development or increase of “COVID-type” tics (such as coughing) [21]. Anecdotally, clinicians in the UK have reported a significant increase in new tic and “tic-like” cases, as well as an increase in tics in young people diagnosed prior to the pandemic, particularly in teenage girls [22‐24]. These tics appear to be atypical in nature, with an acute onset and a circumscribed range of complex vocal and motor tics, often in the absence of what are typically more common simple tics. These previously unusual presentations were uncommon prior to the pandemic and are referred to in the literature as functional tics (a type of functional neurological disorder) due to the fact that they are caused by an abnormality of the functioning of the nervous system rather than an underlying disease and may often be related to psychological or social stress [25, 26].

Beyond ad-hoc clinical reports, there has been limited research into the impact of COVID-19 on tics. A COVID survey of 178 adults with a tic disorder in Europe and North America found that approximately half (48%) of respondents reported a perceived worsening in their tic symptoms, 8% reported tic improvement, with the remainder (44%) reporting no change in tic symptoms. Adults reporting a worsening of symptoms were younger and with more severe existing tics, although no impact of comorbidity was found [27]. To the best of the authors’ knowledge, to date, the only study in young people with tics was a survey conducted in Italy with parent respondents. The survey found that 67% of parents reported worsening of their child’s clinical symptoms since COVID-19, with 20.5% reporting an improvement and 6.7% reporting no change. The findings were not influenced by parental health or their economic situation [23]. However, these studies are limited in that they rely on perceived changes in symptoms since the pandemic, with no direct pre/post pandemic standardised assessment, or in the clinical reports, they are based on individual case studies. To support healthcare professionals in providing appropriate care, there is a need to better understand the impact of COVID-19 and its associated lifestyle changes on CYP with tics in a population-based study. It is also important to identify CYP who might be most vulnerable to developing changes in tics in response to significant environmental stressors [16].

Data from the Online Remote Behavioural Intervention for Tics (ORBIT) randomised controlled trial [28] is uniquely placed to address this question. The trial recruited CYP in England, who were randomised to receive either a remotely delivered behavioural intervention for tics (the intervention group) or remotely delivered psychoeducation (the control group). Participant enrolment and the first baseline measures began in May 2018 and ended September 2019. Participants were followed-up at 3, 6 (phase 1), 12 and 18-months (phase 2) post randomisation. Measures of tic symptoms and severity were recorded using the Yale Global Tic Severity Scale [29] (YGTSS) by trained assessors at each time point. The findings from phase 1 are published and demonstrate that the behavioural intervention was clinically effective and superior to the control arm in improving tic symptoms [30]. For approximately half the participants, the 12-month follow-up assessment coincided with the COVID-19 time period (henceforth, during COVID-19 group), for the other half, the 12-month follow-up was in pre-pandemic times (henceforth, pre-COVID-19 group). Utilising YGTSS data from the control group only (to minimise the confounding impact of treatment on symptom course), we aimed to understand changes in tic symptoms in CYP with a pre-existing tic disorder during the COVID-19 pandemic compared to a group of CYP who had been followed-up pre-pandemic. Although the study was not originally designed to assess this, in this post-hoc analysis we investigated whether tic severity and impairment in CYP with a tic disorder was different between the pre-COVID-19 and during COVID-19 groups. We also investigated for any differences in tic complexity. Tic complexity was specifically assessed as a possible indicator of functional tics. Although similar to classical tics, functional tics tend to be more complex in presentation and do not typically follow the rostro-caudal gradient [31]. We hypothesised that, if COVID-19 had impacted on tics, we would see a difference in YGTSS scores between the pre-COVID-19 and during COVID-19 groups. We also further sought to explore whether this finding was influenced by age, sex, or comorbid symptoms of anxiety and ASD, given suggestion in the literature to date that neurodevelopmentally complex children may have been most vulnerable to increased/changes in tics during the COVID-19 pandemic.