Tourette Syndrome is a neurodevelopmental disorder that affects children, adolescents and adults. The condition is characterized by sudden, involuntary movements and/or sounds called tics. Tics can range from mild/inconsequential to moderate and severe, and are disabling in some cases.
Tourette Syndrome is one type of Tic Disorder. Tics are the primary symptoms of a group of childhood-onset neurological conditions known collectively as Tic Disorders and individually as Tourette Syndrome (TS), Persistent (Chronic) Motor or Vocal Tic Disorder, and Provisional Tic Disorder. These three Tic Disorders are named based on the types of tics present (motor, vocal/phonic, or both) and by the length of time that the tics have been present.
Below are the criteria that a doctor or other health care professional will use to diagnose TS or other Tic Disorders. There is no test to confirm the diagnosis of Tic Disorders, but in some cases, tests may be necessary to rule out other conditions.
Tourette Syndrome (TS), also known as Tourette’s Disorder: 1) At least 2 motor tics and at least 1 vocal (phonic) tic have been present, not necessarily at the same time. 2) Tics may wax and wane in frequency but have occurred for more than 1 year. 3) Tics started to appear before the age of 18. 4) Tics are not caused by the use of a substance or other medical condition.
Persistent (Chronic) Motor or Vocal Tic Disorder: Either motor tics OR vocal tics have been present for more than 1 year; cannot be both motor and vocal tics.
Provisional Tic Disorder: Motor and/or vocal tics have been present for less than 1 year, and have not met the criteria for TS, persistent (chronic) motor, or vocal tic disorder.
Symptoms and Behavior
Motor tics are movements. Simple motor tics include but are not limited to: eye blinking, facial grimacing, jaw movements, head bobbing/jerking, shoulder shrugging, neck stretching, and arm jerking. Complex motor tics involve multiple muscle groups or combinations of movements and tend to be slower and more purposeful in appearance,(e.g., hopping, twirling, jumping).
Vocal (phonic) tics produce a sound. Simple vocal tics include but are not limited to sniffing, throat clearing, grunting, hooting, and shouting. Complex vocal tics are words or phrases that may or may not be recognizable but that consistently occur out of context. In 10-15% of cases, the words may be inappropriate (i.e., swear words, ethnic slurs, or other socially unacceptable words or phrases). This type of vocal tic, called coprolalia, is often portrayed or mocked in the media as a common symptom of TS.
Onset of Tics and Duration
Tics typically emerge between the ages of 5 and 7 years, usually with a motor tic in the head or neck region. They tend to increase in frequency and severity between the ages of 8 and 12 years and can range from mild to severe. Most people with TS see improvements by late adolescence, with some becoming tic-free. A minority of people with TS continue to have persistent, severe tics into adulthood.
Tics can range from mild to severe and, in some cases, can be self-injurious and debilitating. Tics regularly change in type, frequency, and severity—sometimes for reasons unknown and sometimes in response to specific internal and external factors, including stress, anxiety, excitement, fatigue, and illness.
Tics occur in as many as 1 in 5 school-aged children at some time, but may not persist. TS and other Tic Disorders combined are estimated to occur in more than 1 in 50 school-aged children in the United States. TS occurs in 1 in 160 (0.6%) school-aged children, although it is estimated that 50% are going undiagnosed. The reported prevalence for those who have been diagnosed with Tourette is lower than the true number, most likely because tics often go unrecognized. TS affects all races, ethnic groups and ages, but is 3-4 times more common in boys than in girls. There are no reliable prevalence estimates of TS and other Tic Disorders in adults. However, they are expected to be much lower than in children as tics tend to decline into late adolescence.
The causes of TS and other Tic Disorders remain unknown. These conditions tend to occur in families, and numerous studies have confirmed that genetics are involved. Environmental, developmental, or other factors may also contribute to these disorders but, at present, no specific agent or event has been identified. Researchers are continuing to search for the genes and other factors underlying the development of Tic Disorders.
People with TS often have other mental, behavioral, or developmental conditions that may be present prior to the onset of tics. While tics are the primary symptoms, these co-occurring conditions may cause more problems and can be more bothersome than the tics themselves.
Among people diagnosed with TS, it is estimated that 86% have been diagnosed with at least one of these additional conditions. The most common co-occurring conditions include the following:
- Attention Deficit/Hyperactivity Disorder (ADHD): Problems with concentration, hyperactivity, and impulse control.
- Obsessive Compulsive Disorder or Behaviors (OCD/OCB): Repetitive, unwanted intrusive thoughts and/or repetitive behaviors. These thoughts lead to compulsions, which are unwanted behaviors that the individual feels he/she must perform repeatedly or in a certain way.
- Behavioral or Conduct Issues: Aggression, rage, oppositional defiance or socially inappropriate behaviors.
- Anxiety: Excessive worries or fearfulness, including excessive shyness and separation anxiety.
- Learning Disability: Reading, writing, mathematics, and/or information processing difficulties that are not related to intelligence.
- Social Skills Deficits and Social Functioning: Trouble developing social skills; maintaining social relationships with peers, family members, and other individuals; and acting in an age-appropriate manner.
- Sensory Processing Issues: Strong sensory preference and sensitivities related to sense of touch, sound, taste, smells, and movement that interfere throughout the day.
- Sleep Disorders: Trouble falling or staying asleep.