Tourette syndrome

Tourette syndrome is a severe neurological movement disorder characterized by tics that are involuntary, repeated, intermittent movements or vocalizations. It is a genetic disorder that commonly manifests in boys and is often associated with attention deficit hyperactivity disorder (ADHD) or obsessive-compulsive disorder (OCD). Diagnosis is based upon multiple motor tics and at least one vocal tic, lasting for longer than a year, and the exclusion of other suspected medical conditions. Differential diagnoses include transient motor and phonic tics, which last less than a year, Huntington disease, dystonia, myotonia, or stereotypic movement disorder. Treatment is symptomatic and includes behavioral therapy and dopamine antagonists. Approximately 50% of cases resolve by adulthood.

• Sex: ♂ > ♀ ^[1]
• Age of onset: usually 4–6 years of age (tics are most severe between 10–12 years of age and then decline during adolescence) ^[2]

Epidemiological data refers to the US, unless otherwise specified.

• Hypothesized to be a combination of environmental, social, psychological, and genetic factors
• Associated conditions
  • ADHD and/or OCD (most common)
  • Learning disabilities
  • Sleep disorders
  • Conduct disorder and oppositional defiant disorder
  • Mood and anxiety disorders

• Tics: sudden and rapid involuntary, intermittent, nonrhythmic movements or vocalizations without any recognizable purpose
  • May wax and wane in frequency
  • Temporarily suppressible
  • Premonitory urge: An urge or sensation preceding the tic is relieved by its onset.

Tourette syndrome is a clinical diagnosis based on all of the following:

• Multiple motor tics and at least 1 vocal tic with a variable anatomical location, frequency, number, complexity, type, or severity over time
• Onset before 18 years of age
• Lasting > 1 year
• Not explained by other medical conditions or substance use (e.g., cocaine) ^[3]

Other tic disorders ^[4]

Sporadic transient tic disorder

A subtype of tic disorder particularly common in children, which manifests with motor or vocal tics that occur over a period of less than one year before resolving.

• Motor and/or vocal tics
• Age of onset: < 18 years
• Symptoms occur for less than 1 year (resolve spontaneously)
• Not explained by any other medical conditions or substance abuse
• Do not meet the criteria for Tourette syndrome

Persistent motor tic disorder or persistent vocal tic disorder

Subtypes of tic disorder particularly common in children, which manifests with motor or phonic tics only.

• Motor or vocal tics (not both)
• Age of onset: < 18 years
• Persist > 1 year
• Not explained by any other medical conditions or substance abuse
• Do not meet the criteria for Tourette syndrome

Adult-onset tic disorder ^[5][6]

• Onset of tics after the age of 18 years
• Primary tics (idiopathic): not explained by other medical conditions or substance use (e.g., cocaine); very rare
• Secondary tics: due to a medical condition (e.g., brain lesions, neurodegenerative disease) or substance use
• Recurrence of childhood-onset tics that initially resolved after childhood

Other differentials

• Stereotypic movement disorder
  • Stereotypic, uncontrolled, repetitive movements lasting ≥ 4 weeks
  • More common in children, especially boys, with neurological disorders and developmental delay
  • Includes rocking movements, hair pulling, hair twisting, and self-destructive behavior (e.g., head banging, picking at skin, hitting oneself) ^[7][8]
• Tardive dyskinesia
• Huntington disease
• Sydenham chorea in rheumatic fever
• Spasmus nutans (nodding spasm)
• Myoclonus
• Oromandibular dystonia
• Blepharospasm
• Hemifacial spasm

The differential diagnoses listed here are not exhaustive.

• Support: counseling and education (for both caregivers and patients)
• Behavioral therapy
  • Indicated for mild, nondisabling symptoms
  • Involves habit reversal training or Comprehensive Behavioral Intervention for Tics (CBIT)
• Medical therapy ^[9]
  • Indicated for severe or refractive cases despite behavioral therapy
  • Alpha-adrenergic agonists: guanfacine; (often first-line therapy), clonidine (very sedating)
  • Typical neuroleptic drugs: pimozide, haloperidol, fluphenazine (FDA-approved but may cause tardive dyskinesia)
  • Atypical neuroleptic drugs: risperidone (increasingly preferred because of fewer side effects)
  • Dopamine depleting drugs: tetrabenazine (may be used as first-line therapy to avoid side effects of neuroleptic drugs, i.e., dopamine blockade) ^[10]
• Deep brain stimulation (DBS): an alternative therapy in therapy refractory cases with severe tics ^[11]

Treatment of associated conditions (i.e., ADHD or OCD) can improve symptoms.

• Symptoms improve during adolescence. ^[2]
• May resolve spontaneously by 18 years of age (50% of cases) ^[12]