What are Tics and Tourette’s Disorder?
Tics are sudden, rapid, recurrent, non-rhythmic, involuntary movements or sounds. They can be described as simple (involving only one or a few muscles or sounds) or complex (more purposeful, and involving groups of muscles or syllables, words or phrases). Tics may be experienced as irresistible, but can be suppressed temporarily, and are often preceded by an uncomfortable urge or sensation. Tics are very common, and may occur in up to 20 percent of school-age children.
Tourette’s Disorder, also known as Tourette Syndrome (TS), is the most complex of the tic disorders. TS is a childhood-onset, neuropsychiatric condition characterized by multiple motor and vocal tics lasting more than one year. While current diagnostic criteria require onset before age 18, the vast majority of patients have onset by about 6 years of age. Both motor and vocal tics must be present, though not necessarily at the same time. Tics frequently occur in bouts, and wax and wane in frequency and intensity over time. Individuals who seek treatment for TS may also have other commonly occurring comorbid (associated) conditions such as Obsessive Compulsive Disorder, Attention Deficit Hyperactivity Disorder, and Anxiety or Mood Disorders.
Symptoms of Tics and Tourette’s Disorder
Tics vary from mild to severe, but even in patients who seek care, symptoms are usually in the mild to moderate range. Tics can occur suddenly, last for varying lengths of time, and may temporarily decrease with concentration or distraction. During times of stress or excitement, tics may increase in frequency or intensity. Tics are characterized as either motor or vocal, and then subdivided into simple and complex. The following are common examples:
- Motor tics
- Simple - eye blinking, facial grimacing, head jerking, arm or leg thrusting
- Complex - jumping, smelling, touching things or other people, twirling around
- Vocal tics
- Simple - throat clearing, coughing, sniffing, grunting, yelping, barking
- Complex - repeating syllables, words or phrases; less common, saying obscene or socially unacceptable words (called coprolalia)
Many people with TS also have one or more of the following problems:
- Obsessions (intrusive, repetitive thoughts, words, or images)
- Compulsions (repetitive and ritualistic behaviors)
- Attention Deficit Hyperactivity Disorder (ADHD)
- Mood and anxiety disorders (separation anxiety, phobias, social anxiety)
- Explosive outbursts (“rage attacks”)
- Learning disorders
- Difficulties with impulse control
- Sleep disorders
While tics may occur throughout life, older adolescents with TS often experience reduction in tic severity.
Causes of Tics and Tourette’s Disorder
The cause of TS has not been established. However, current research presents considerable evidence that brain chemicals, called neurotransmitters, are likely involved. In many cases, TS is inherited. This genetic predisposition may express itself as TS, a milder tic disorder, or as obsessive-compulsive symptoms or disorder with no tics at all. Specific genes are not known, but studies are currently under way at our center and around the world to better understand the genetic underpinnings of the disorder.
Risk Factors For Tics and Tourette’s Disorder
The following factors increase the risk of developing tics, and should be shared with your physician:
- Family history of TS
- Other tic disorders
- Obsessive Compulsive Disorder
- Male gender (males are three to four times more likely to be affected)
There are also many secondary causes of tics, which include the following:
- Other neurological disorders
- Hereditary disorders
- Carbon monoxide poisoning
- Traumatic brain injury
- Cerebral infections
- Some medications and substances