Tourette's Syndrome & Other Tic Disorders

Definition

Tourette's Syndrome (TS) is a neurodevelopmental disorder characterized by multiple motor tics and at least one vocal (phonic) tic persisting for more than one year, often beginning in childhood. Other tic disorders include persistent (chronic) motor or vocal tic disorder and provisional (transient) tic disorder.

Epidemiology

• Prevalence: ~0.3–1% in children and adolescents worldwide.
• Male predominance (~3–4:1 male to female ratio).
• Onset usually between ages 4–6 years, peak severity at 10–12 years.
• Tics often improve in late adolescence; some persist into adulthood.
• Comorbidities are common: ADHD, OCD, anxiety, learning disorders.

Etiology

• Genetic predisposition: multiple genes implicated; strong family history.
• Neurobiological factors: dysfunction of cortico-striato-thalamo-cortical circuits.
• Dopaminergic dysregulation in basal ganglia.
• Environmental triggers: prenatal maternal stress, infections (PANDAS), psychosocial stressors.
• Interaction of genetic and environmental factors contributes to tic expression.

Pathophysiology

• Abnormal activity in basal ganglia and related cortical circuits.
• Dysregulated dopamine and other neurotransmitters (GABA, serotonin) influence tic generation.
• Impaired inhibition of unwanted movements results in motor and vocal tics.
• Sensory premonitory urges precede tics; temporary relief occurs after tic execution.
• Neurodevelopmental delay or dysfunction contributes to tic severity and comorbidities.