Tourette’s syndrome and other tic disorders

Tourette’s syndrome and other tic disorders

DIAGNOSING TOURETTE’S SYNDROME

Based on the 5th Edition of the Diagnostic and Statistical Manual of Mental Disorders, abbreviated DSM-5, several features are required to diagnose Tourette’s syndrome.1

  1. Two or more motor tics (meaning at least two tics with movements that appear differently from one another) and the presence of at least one vocal tic. The motor and vocal tics can be simple or complex.
  2. The onset of tics before 18 years of age.
  3. Tics occur many times per day, every day or nearly every day.
  4. Tics have been present longer than one year.

TOURETTE’S SYNDROME FEATURES

Patients with Tourette’s syndrome typically have tic onset at 4 to 6 years of age, develop maximal severity of tics at 10 to 12 years of age, and will have improvements in tics by adulthood; although 90% of adults continue to have some tics.2 Comorbidities are common with tic disorders, especially Tourette’s syndrome. A comorbidity is defined as an additional medical condition found commonly with the primary condition, in this case Tourette’s syndrome. For example, patients with Tourette’s syndrome are more likely than individuals without Tourette’s syndrome to have attention deficit-hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Depression is also more common in patients with Tourette’s syndrome. Only 15% of patients with Tourette’s syndrome have no other comorbidities.3 The medical management of Tourette’s syndrome should always include the assessment of comorbidities and their treatment when present.

When tics are present but patients dot meet criteria for Tourette’s syndrome, other tic disorders are diagnosed: persistent (chronic) motor or vocal tic disorder or provisional tic disorder.

PERSISTENT (CHRONIC) MOTOR OR VOCAL TIC DISORDER1

  1. One or more motor tics or vocal tics are present.
  2. The onset of tics begins before 18 years of age.
  3. Tics occur many times per day, every day or nearly every day.
  4. Tics have been present longer than one year.

PROVISIONAL TIC DISORDER1

  1. One or more motor or vocal tics are present.
  2. The onset of tics begins before 18 years of age.
  3. Tics have been present for less than one year.

Since the provisional tic disorder covers all types of tics (and tic frequencies) of less than one year in duration, all patients with tic onset before 18 years of age will fall into one of the three diagnostic categories.

COMMENT

Having a diagnosis of Tourette’s syndrome does not always mean that medical treatment is needed. Some patients with Tourette’s syndrome have normal daily function without any medical intervention. The next posts will discuss when medical treatments should be considered for tic disorders and the types of treatments available.

References

¹American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 5th ed. Washington, D.C.: American Psychiatric Association; 2013

²Robertson MM. A personal 35 year perspective on Gilles de la Tourette’s syndrome: assessment, investigations, and management. Lancet Psychiatry. 2015;2:88-104.

³Hirschtritt ME, Lee PC, Pauls DL, et al. Lifetime prevalence, age of risk, and genetic relationships of comorbid psychiatric disorders in Tourette’s syndrome. JAMA Psychiatry. 2015;72:325-333.