Overview

• Definition: Disorder characterized by multiple motor and vocal tics.
• Prevalence:
  • Overall prevalence of 1% in children aged 5–18 years.
  • Prevalence varies from 0.4–3.8% depending on country and diagnostic methodology (Eysturoy et al., 2015).
• Associated Conditions: Often includes psychiatric manifestations, notably ADHD and OCD symptoms.

Aetiology

• Genetic Factors:
  • Familial occurrence due to genetic or environmental influences.
  • Twin studies: 50–70% concordance in monozygotic twins, 9% in dizygotic twins.
  • Suggested complex inheritance involving a major gene and multiple additional factors (Walkup et al., 1996).
  • No single locus established (Pascher et al., 2004; Keen-Kim and Freimer, 2006).
  • Dopaminergic and serotonergic pathways involvement inconsistent, but DRD2, MAO-A, and DAT1 supported by findings.
  • Multiple implicated genes, with SLITRK1 being prominent (Paschou, 2013).
  • Deletions of 16p13.11, 22q11, and NRXN1 recorded in some cases (McGrath et al., 2014).
• Demographics:
  • Three to four times more frequent in boys.
  • Psychological events may trigger onset and modulate evolution, but their role is secondary.
• Mechanism:
  • Unclear with no known pathological basis.
  • MRI evidence of decreased basal ganglia volume, especially the striatum.
  • Likely involvement of dopamine transmission due to genetic and pharmacological evidence.

Clinical Features

• Diagnostic Criteria:
  • Multiple motor tics and one or more vocal tics present at some time during the illness, though not necessarily concurrently.
  • Tics occur many times daily, nearly every day, or intermittently for more than 1 year without a tic-free period exceeding 3 months.
  • Significant impairment in everyday life.
  • Onset before 18 years of age.
  • Disturbance not attributable to substances or a general medical condition.
• Comorbid Manifestations:
  • Present in more than half of the cases.
  • OCD observed in about 30% of patients.
  • ADHD common, along with various behavioral and psychiatric problems, causing significant distress.

Differential Diagnosis

• Conditions to Differentiate From:
  • Polymyoclonus and chorea, especially Sydenham chorea.
  • Stereotypies and compulsive behaviors.
• Considerations for Abrupt, Infection-Associated Onset:
  • Paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) (Snider and Swedo, 2004).
  • PANDAS causes multiple tics, abnormal movements, and psychiatric manifestations, especially OCD.
  • Antibodies to basal ganglia neurons reported, thought to cross-react with streptococcal antibodies (Church et al., 2003; Singer, 2004).
• Recent Developments:
  • Recognition of non-streptococcus-associated abrupt onset leading to term 'paediatric acute neuropsychiatric syndrome' (PANS).
  • PANDAS/PANS characterized by acute, dramatic onset and potential for complete remission, unlike idiopathic OCD and Tourette syndrome.
  • Therapeutic attempts with antibiotics, corticosteroids, intravenous immunoglobulin, and plasma exchange, restricted to clear-cut cases of PANDAS and PANS and managed by knowledgeable physicians.

Treatment of Tourette Syndrome

• No Specific Treatment Needed:

  • In many cases, no specific treatment is required.
  • Correct diagnosis and informing parents and child about the nature of Tourette syndrome is crucial.
  • Emphasize that Tourette syndrome is not a psychological problem and that tics do not indicate a severe underlying psychiatric or neurological disorder.
  • ADHD, OCD, and anxiety disorders can occur and can be treated.
  • Peak severity of tics typically occurs around 10–12 years of age, with potential for improvement or remission later.

• Behavioral and Psychological Approaches:

  • Increasingly popular and effective.
  • Includes tic reversal therapy (Piacentini et al., 2010).
  • Clonidine may also be effective.

• Pharmacological Treatments:

  • Severe Cases:
    • Dopamine receptor antagonists are indicated.
    • Pimozide is often used at low doses (1–4 mg/day) due to relatively few side effects (Comings, 1990).
    • Haloperidol should only be used if risperidone fails.
    • Risperidone and pimozide are more effective than placebos, though they have significant side effects (The Cochrane Library, 2007).
  • Associated Psychiatric Disorders:
    • Treatment of ADHD, OCD, and anxiety disorders is as important as treating the tics.

• Resistant Cases:

  • Electrical deep brain stimulation has been effective (Larson, 2008; Schrock et al., 2015).

Outcome

• In the majority of cases, the outcome is relatively favorable.
• Tics often become less prominent, and patients learn to live with the condition.
• Long remissions are not rare.

References

• APA American Psychiatric Association (2013) Diagnostic and Statistical Manual of Mental Disorders, 5th edn. Arlington, VA: APA Publishing.
• Church AJ, Dale RC, Lees AJ, et al. (2003) Tourette’s syndrome: a cross sectional study to examine the PANDAS hypothesis. J Neurol Neurosurg Psychiatry 74: 602–7.
• Cohen SC, Mulqueen JM, Ferracioli Odi E, et al. (2015) Metaanalysis: risk of tics associated with psychostimulant use in randomized, placebo-controlled trials. J Am Acad Child Adolesc Psychiatry 54: 728–36.
• Comings DE (1990) Tourette Syndrome and Human Behavior. Duarte, CA: Hope Press.
• Eysturoy AN, Skov L, Debes NM (2015) Genetic predisposition increases the tic severity, rate of comorbidities and psychosocial and educational difficulties in children with Tourette Syndrome. J Child Neurol 30: 320–5.
• Fernandez-Alvarez E, Aicardi J (2001) Movement Disorders in Children. International Review of Child Neurology Series. London: Mac Keith Press for the International Child Neurology Association.
• Jankovic J, Fahn S (1986) The phenomenology of tics. Mov Disord 1: 17–26.
• Keen-Kim D, Freimer NB (2006) Genetics and epidemiology of Tourette syndrome. J Child Neurol 21: 665–71.
• Larson PS (2008) Deep brain stimulation for psychiatric diseases. Neurotherapeutics 5: 50–8.
• McGrath LM, Yu D, Marshall C, et al. (2014) Copy number variation in obsessive-compulsive disorder and Tourette syndrome: a cross-disorder study. J Amer Acad Child & Adol Psych 53: 910–9.
• Pascher P, Feng Y, Pakstis AJ, et al. (2004) Indication of linkage and association of Gilles de la Tourette syndrome in two independent family samples: 17q25 is a putative susceptibility region. Am J Hum Genet 75: 545–60.
• Paschou P (2013) The genetic basis of Gilles de la Tourette Syndrome [Review]. Neurosci & Biobehav Rev 37: 1026–39.
• Piacentini J, Woods DW, Scahill L, et al. (2010) Behavior therapy for children with Tourette Disorder: a randomized controlled trial. JAMA 303(19): 1929–37.
• Schrock LE, Mink JW, Woods DW, et al. (2015) Tourette syndrome deep brain stimulation: a review and updated recommendations. Mov Disord 30: 448–71.
• Shapiro AK, Young JG, Fenberg TE (1988) Gilles de la Tourette Syndrome, 2nd edn. New York: Raven Press.
• Snider LA, Swedo SE (2004) PANDAS: current status and directions for research. Mol Psychiatry 9: 900–7. The Cochrane Library (2007) Issue 4, MEDLINE (1950–April 2007).
• Walkup JT, Labuda MC, Singer HS, et al. (1996) Family study and segregation analysis of Tourette syndrome: evidence for a mixed model of inheritance. Am J Hum Genet 59: 684–93.