Biology 202
1999 First Web Reports
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Tourette Syndrome

Nicki Pollock

Tourette Syndrome, or TS, affects approximately one hundred thousand Americans of whom you will find in a variety of professions and social settings (7). It is a neurological disease which is characterized by repeated and involuntary body movements and vocal sounds. Before TS was known to be a health problem uncontrollable by the patient, it was seen as nervousness, possession by a spirit, epilepsy or simply as bad habits (5). Today it is known that imbalances in certain brain chemicals are what causes the symptoms of this disease. It is interesting to examine TS and use it as a tool for better understanding (in part) how, in what quantity, and at what level the brain (and the nervous system as a whole) contribute to and influence behavior.

Tourette Syndrome is an inherited neurological disorder. While it can be, and very often is, affected by environmental factors, it is at its roots a product of a dominant genetic mutation. The symptoms, which can vary >from patient to patient in kind and severity, usually appear before the age of eighteen; some include eye blinking, repeated throat clearing, sniffing, arm thrusting, kicking, vocalized obscenities or jumping (2). This disease affects all ethnic groups and males three to four times more than females. The symptoms actually tend to lessen, not worsen, with age (6).

Other conditions usually associated with TS are ADHD (attention deficit hyperactivity disorder) and OCD (obsessive-compulsive disorder) which can also be manifestations of TS (2). These are psychological and behavioral difficulties which border on neurology and psychiatry. Also, other mental disorders such as anxiety and depression may develop not as a direct product of TS, but rather the symptomology of living with a long-term illness.

There are various theories as to the exact causes and brain chemicals involved in the manifestation of TS. It was found that drugs which stimulate the production of the brain chemical dopamine can induce "tics" (7). Some ideas about how this is happening in TS victims suggest that there may be "supersensitive" receptors to dopamine in specific areas of the brain, and that this area under normal conditions would act like a "brake" on the movements made on purpose (3). Or, there just may be higher than normal levels of dopamine production and use in the patient. Still other scientists say that dopamine may not be the only chemical involved. They have also found differing levels of a chemical called serotonin in TS patients (where it was high) and unaffected people (where it was lower). Other theories include increase in red-cell choline, imbalance in central nervous system dopamine and acetylcholine, and motor movements originating in the anterior cingulate cortex (1). Locating the genetic basis of the disease can help doctors and scientists better aid in treating those with TS.

While there is no medication which relieves every symptom of TS, there is the possibility of improvement if the patient does not have serious side effects to the medications, of which there are a variety (i.e. pimozide, risperidone, clonidine) (8). Researches have found that the drug haloperidol acts on dopamine and in turn calms the patient. Haloperidol works by blocking the receiving areas on receptor cells where dopamine passes on messages (7). It should be noted however that most patients function well enough without drug treatment, and that treatment of this nature should be monitored carefully. Usually the lowest dose of a drug specifically geared to subdue the strongest symptom is prescribed (2). There is also the option of non-medicated treatments. Being aware of food allergies, chemical toxins, and environmental hazards which may worsen TS symptoms seems to help in some cases (4).

Now the task is to find a way for TS to help one make more sense of the relationship between brain and behavior, at least in part because obviously looking at one neurological disease is not going to solve the entire mystery, but it can provide some insights and spark new questions. The idea that the brain "allows" actions to happen is to most people a radical way to think of behavior. Most think of the nervous system as acting as a director of sorts, telling which body parts to move and getting everything to move in a coordinated fashion. A new way to try to think of the brain is as an "allower". Body motions would quite possibly happen all the time if the brain were not in a place to inhibit those actions which would just occur, as in TS. As people, we grow and gradually learn to control ourselves more with each year (particularly as children) physically, mentally, and verbally. In TS patients, however, the imbalance of their brain chemicals does not allow for them to always be in control voluntarily. It is interesting though that many cases of TS involve transient symptoms where the patient has bouts of tics or other effects and then at other times is fine.

The example of TS also brings to the forefront the reality that brain and nervous system function really go down to the chemical and molecular level. Individual cells and receptors on these cells can be responsible for a whole breadth of malfunctions if they are not working properly. Behavior is not simply the physical movements we see happening, but is actually much more intricate and involves very specific parts of the nervous system at various times.

TS does not necessarily have to be thought of as a disease (6). Some patients do not wish to be seen as victims and revel in the fact that they have overcome a challenge to live very successful and rewarding lives. It can be thought of instead as merely a different way of behaving; a different way for the nervous system to function, which it certainly is. Because Tourettes is so much more easily diagnosed today it is becoming more and more accepted and recognized. Diagnosis and treatment can only be furthered by the continued study of genetics, neurology and also psychiatry.

WWW Sources

1)Gilles De La TouretteSyndrome

2)Tourette Syndrome Association, Inc.

3)What Makes Tics Tick? Clues Found In Tourette Twins' Caudates

4)Home Page of Latitudes: A Publication of the Association for Comprehensive Neuro Therapy

5)Guide to the Diagnosis and Treatment of Tourette Syndrome

6)The pre-FAQ

7)Brain Briefings: Tourette's Syndrome and Dopamine

8)Virtual Hospital: Medical Treatment of Tourette Syndrome

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