Causes Of Tourette Syndrome
What causes Tourette syndrome?
In the majority of cases of Tourette syndrome there's no identified cause. We are very suspicious that Tourette syndrome is genetically transmitted in the majority of cases. There are some other instances where people may use medications that could potentially bring out tic-like behaviors. These are usually psychiatric medications, potent tranquilizing medications such as haloperidol could cause a tic-like disorder. Sometimes brain injury or even an in utero maldevelopment of the brain, so called encephalopathy, something that people may be born with. Mental retardation can be associated with a tic as well. But again the majority of people with Tourette syndrome or tic don't have another underlying disorder or other medications or brain infections that are causing their symptoms.
What role do genetics have in acquiring Tourette syndrome?
Tourette syndrome seems to be a genetic disorder. It does run in families. And the gene, once it's transmitted, may show itself in a variety of ways. Some people who get the gene may have primarily tics. Other people may have mostly behavioral changes, and these obsessive compulsive symptoms may be the main manifestation of the gene. But we do think, in the majority of cases, Tourette syndrome is genetically transmitted and that it does run in families. The exact mechanism of genetic transmission is not entirely clear. It was thought at one point to be perhaps what's called "autosomal dominant," meaning that if one of your parents has the gene, you have a 50/50 chance of getting the gene yourself. It's less clear that that's the method of transmission now. It may involve, in fact, multiple genes for different modifiers of a single gene. The exact genetic mechanism is not completely worked out at this point.
What diseases or physical conditions can cause Tourette syndrome?
Some people with underlying brain disorders that are present from birth may have tick, or even the symptoms of Tourette syndrome, meaning a combination of both motor and vocal ticks. That's a possibility. It's been described in some people with autism for example. But then again, the majority of people with Tourette don't have another underlying neurological diagnosis.
What role do viruses and bacteria play in Tourette syndrome?
Rarely people have had brain infections which are referred to as encephalitis or infections which are on the surface of the brain, meningitis. Once they recover they could have movements very similar to tic or frankly tic, but that would be an uncommon cause or source of tics syndrome or Tourette syndrome.
What role does race play in Tourette syndrome?
Tourette's is found worldwide and it's not unique to any specific race or ethnicity, nor are specific people in various parts of the world spared from Tourette syndrome. It may show itself slightly differently but it still does show up. It's been reported for example that people in Japan who have Tourette's syndrome are less likely to have this unusual symptom of coprolalia, or the uttering of obscenities. But otherwise it's pretty similar worldwide.
What could trigger a tic?
The phenomenon of tic is actually quite interesting. People with tic will have an internal sense of discomfort, something that's bothering them, and it's very hard for people with tic to put it into words. It's really a very visceral type of feeling that they, at least temporarily, flesh out, or get rid of by the tic process itself. So tic can be thought of as both a sensory and, in many cases motor, or vocal, phenomenon, where people have this internal feeling that's uncomfortable, which they get rid of or expel somehow by the tic movement or by the vocal tic.
