Neurology & Pediatrics & Psychiatry
Tourette's syndrome
Tourette syndrome (TS) - described by French neurologist Georges Gilles de la Tourette in 1885 - is a neuropsychiatric developmental disorder characterized by the presence of chronic multiple tics (motor and vocal) beginning in childhood, whose pathophysiology involves deregulation of cortico-striato-thalamo-cortical (CSTC) circuits with dopaminergic hyperactivity in the basal ganglia. With a prevalence of 0.5 to 1 % in the paediatric population + a clear male predominance (H:F = 3-4:1) and a usual age of onset between 5 and 7 years, ST is often unrecognized or diagnosed late - partly because tics tend to regress or attenuate significantly in adolescence in 50 to 70 % of patients, and because coprolalia (involuntary emission of obscene or socially unacceptable words) - popularized by media representations - is present in only 10 to 15 % of patients with ST and is not necessary for diagnosis. The most important and often overlooked clinical feature is the presence of a premonitory impulse (premotor urge) - an unpleasant subjective bodily sensation (tension + tingling + pressure) which immediately precedes the tic and subsides transiently after it has been performed, analogous to the urge to sneeze + and which distinguishes tics from other involuntary movements. ST rarely occurs in isolation: in 85-90 % of cases, it is accompanied by neuropsychiatric comorbidities that are often more disabling than the tics themselves - mainly attention deficit disorder with or without hyperactivity (ADHD - 50-70 %) and obsessive-compulsive disorder (OCD - 30-50 %). Treatment should therefore focus on the comorbidities that are most disabling for the child's day-to-day functioning, and not systematically on the tics themselves.
DSM-5 diagnostic criteria
- Criterion A - Multiple motor tics and at least one vocal tic: present at some point during the course of the disease + but not necessarily simultaneously
- Criterion B - Duration : tics present for more than 1 year since onset of first tic
- Criterion C - Start : onset before age 18
- Criterion D - Exclusion : tics are not attributable to the physiological effects of a substance (cocaine + levothyroxine + methylphenidate overdose) or another medical condition (Huntington's chorea + encephalitis + Lesch-Nyhan syndrome)
- Other tic disorders (DSM-5) : persistent (chronic) motor or vocal tic disorder = motor OR vocal tics alone (not both) for > 1 year + temporary tic disorder = motor and/or vocal tics for > 1 year > years 1 year
Characteristics of tics
- Simple motor tics : blinking +++ (often first tic) + grimaces + shoulder shrugs + head movements + sniffing + abdominal tension
- Complex motor tics : coordinated motor sequences (jumping + touching objects + imitative behaviours = echopraxia + obscene behaviours = copropraxia)
- Simple vocal tics : throat clearing + sniffing + coughing + tongue clicking + grunting
- Complex vocal tics : repetition of own words or sounds (palilalia) + repetition of others' words (echolalia) + emission of obscene or socially unacceptable words (coprolalia - present in only 10-15 % of STs)
- Premonitory impulse (urge): unpleasant body sensation preceding the tic + characteristic of ST + helps distinguish tics from other involuntary movements (chorea + myoclonus + tremor) + patients can partially suppress their tics voluntarily (for a few seconds to minutes) but at the cost of increasing tension
- Temporal variability : tics fluctuate over time (alternating between calmer periods and flare-ups) + change in nature + worsen with stress + fatigue + excitement + diminish during absorbing activities (video games + sports + musical instruments)
Comorbidities - often more disabling than tics
- TDAH (50-70 %) : attention deficit + impulsivity + hyperactivity → major impact on schooling and social relationships → priority treatment: methylphenidate (Ritalin® + Concerta®) or amphetamines - stimulants may slightly aggravate tics in some patients, but this risk is modest and does not contraindicate their use if ADHD is disabling + atomoxetine + clonidine + guanfacine (effective on ADHD and tics)
- TOC (30-50 %) : obsessions + compulsions → time-consuming rituals + anxiety + treatment: CBT (exposures with response prevention) + SSRIs (sertraline + fluoxetine) in progressive doses → NB: ST-related compulsions are often «sensorimotor» (touch + symmetry + counting) rather than contamination-focused
- Anxiety (30-40 %) : social anxiety (shame of tics + others' gaze) + generalized anxiety
- Learning difficulties (20-30 %) : dyslexia + dysgraphia + auditory processing difficulties
- Sleep disorders : difficulty falling asleep + parasomnias + tics persist during light sleep (stage N1-N2) but diminish during deep sleep and REM sleep
- Conduct disorders + social difficulties : impulsivity + inappropriate behavior + peer rejection → significant impact on self-esteem and quality of life
Treatment
| Treatment | Mechanism / Molecules | Indications and remarks |
|---|---|---|
| CBIT - Behavioral therapy (1st line) | Comprehensive Behavioral Intervention for Tics = habit reversal training (HRT) + relaxation + cognitive restructuring + psychoeducation | First-line treatment of moderate-intensity tics + proven efficacy (randomized trials) + 30-50 % improvement in tic severity + no side effects + recommended before medication if tics are moderate |
| Clonidine (alpha-2 agonist) | Alpha-2 adrenergic receptor agonist → reduction of noradrenergic tone + beneficial effects on tics AND ADHD | First-line pharmacology + moderate efficacy on tics (30-40 % reduction) + also effective on ADHD + well tolerated + side effects: somnolence (often lessens with time) + orthostatic hypotension + dry mouth + transdermal patch available |
| Guanfacine (alpha-2 agonist) | Same mechanism as clonidine + more selective of alpha-2A receptors + less sedative | Alternative to clonidine + better cognitive tolerance + particularly useful if ADHD predominant + LP form (Intuniv® XR) available in Canada |
| Aripiprazole (atypical antipsychotic) | Partial agonist of D2 and D3 receptors → stabilization of dopaminergic transmission in basal ganglia | Effective on moderate to severe tics + favorable adverse-effect profile (fewer extrapyramidal effects than haloperidol + less weight gain than risperidone) + start at 1-2 mg/d + progressive titration to 10-20 mg/d |
| Haloperidol (typical antipsychotic) | Potent D2 receptor antagonist → reduced striatal dopaminergic hyperactivity | Very effective on tics (70-80 % reduction) + but limiting adverse effects: tardive dyskinesia + extrapyramidal syndrome + akathisia + sedation + dysphoria → reserved for severe refractory forms + very low doses (0.25-2 mg/d) |
| Pimozide | D2 antagonist + calcium channel blocker | Effective but risk of QTc prolongation → ECG mandatory before and during treatment + risk of drug interactions (CYP3A4) |
| Vesicular monoamine inhibitors (VMAT2) | Tetrabenazine + deutetrabenazine (Austedo®) + valenabenzine (Ingrezza®) → presynaptic dopamine depletion → tic reduction | FDA-approved for ST tics (valenabenzine 2023) + lower risk of tardive dyskinesia + side effects: somnolence + depression + akathisia + limited access in Canada |
| Botulinum toxin injections | Local chemical denervation of the muscles generating the most disabling tics → disappearance or reduction of the targeted tic | Useful for very disabling focal motor tics (painful cervical tic + ocular tic) + or localized vocal tics (vocal cords) + duration of effect 3-4 months + reduced premonitory urge in studies |
ℙ️
Tourette's syndrome is often more disabling because of its comorbidities (ADHD + OCD + anxiety) than because of the tics themselves. Initial assessment should systematically identify these comorbidities - often under-diagnosed - and prioritize their treatment according to their functional impact on the child's schooling and social life. Many children do not need medication for tics if they are moderate and do not interfere with functioning - psycho-education of the child + the family + and the school is the fundamental therapeutic pillar.
Medical consultation recommended
Consult a physician if a child presents with repetitive involuntary movements + involuntary sounds + or unexplained repetitive behaviors for more than a few weeks - a neurological or pediatric evaluation will help distinguish Tourette syndrome from other causes of tics (medications + organic causes) and evaluate associated comorbidities (ADHD + OCD). For the initial evaluation of tics in children + psychoeducation + referral to pediatric neurology and behavioral therapy (CBIT), Clinique Omicron offers consultations at its points of service in Quebec and via telemedicine. To book an appointment, visit cliniqueomicron.ca.
Consult at Clinique Omicron
Clinique Omicron's specialized physicians and nurse practitioners (IPS) assess the child's tics according to DSM-5 criteria, screen for associated comorbidities (ADHD + OCD + anxiety + learning difficulties), prescribe psycho-education for the child + family + school team, initiate alpha-2 agonists (clonidine + guanfacine) for moderate tics or associated ADHD, refer to pediatric neurology or child psychiatry for severe or complex forms, and coordinate with therapists trained in CBIT. Consultations are available at several points of service in Quebec and via telemedicine. To book an appointment, visit cliniqueomicron.ca.
The content of this page is provided for information purposes only and does not replace the advice of a physician, pediatric neurologist or child psychiatrist. Coprolalia (involuntary emission of obscene words) is present in only 10 to 15 % of Tourette's syndromes - do not wait for this symptom to make the diagnosis. Tics subside spontaneously in 50 to 70 % of patients by adolescence.
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