Tourette’s Syndrome: A critical review Introduction Essay

Tourette’s Syndrome: A critical review Introduction Essay

Gilles de la Tourettes Syndrome (TS) is a sporadic or inherited complex neuropsychiatric disorder (not an illness) influenced by neurological, psychological, and sociological factors. It is characterised by involuntary tics – sudden, rapid, recurrent non-rhythmic movements or noises that occur repeatedly in the same way (Temple, 2003). The symptoms include: both multiple motor tics and one or more phonic tics (which may or may not include vocalisations and which sometimes include outbursts of swearing) present at some time during the disorder although not necessarily simultaneously. Tics occur many times a day (usually in bouts) nearly every day or intermittently throughout a span of more than one year. Periodic changes are expected in the number, frequency, type and location of the tics; waxing and waning of their severity is also common. Symptoms can sometimes disappear for weeks or months at a time. TS affects about 1 in every 2000 people (Robertson, 1989).
TS syndrome is not considered a mystery anymore, among the circles of neuroscience and clinical psychology, as it has been in the past. On the other hand, there are still some controversial issues regarding this disorder. These are the ways in which Tourettes should be treated (what medications should be prescribed to people with TS) and the matter whether Tourettes should be actually considered a Higher Executive Function deficit or not. There is also the issue of the inheritability of the disorder. There is evidence of TS co-morbidity with disorders like obsessive compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD), a fact which actually suggest inheritability of the disorder, since these disorders are also considered (by most scientists) inheritable. However, as Nass and Bressman (2002) state, the relationships between both ADHD and TS and OCD and TS are complex and not yet clear. In addition to this, until now linkage analysis has pointed to a number of chromosomal locations, but has failed to identify a clear candidate gene(s).


Treating TS


Treating TS has been a controversial issue among scientist for years. The kind of medication that should be prescribed to people with TS is currently under debate mainly because TS is frequently accompanied along with other disorders such as OCD or ADHD. Due to that there is no one medication that is absolutely beneficial for all persons with TS. Moreover, none of the available medications for TS completely eliminates symptoms and, in addition, all medications have side effects. Instead, the available TS medications are only able to help reduce specific symptoms. Some patients who require medication to reduce the frequency and intensity of the tic symptoms may be treated with neuroleptic drugs such as haloperidol and pimozide (Abuzzahab & Brown, 2001). These medications are usually given in very small doses that are increased slowly until the best possible balance between symptoms and side effects is achieved.
Recently scientists have discovered that long-term use of neuroleptic drugs may cause an involuntary movement disorder called tardive dyskinesia (Nass & Bressman, 2002). However, this condition usually disappears when medication is discontinued. Short-term side effects of haloperidol and pimozide include muscular rigidity, drooling, tremor, lack of facial expression, slow movement, and restlessness. These side effects can be reduced by drugs commonly used to treat Parkinson’s disease (like ardan or akinitol). Other side effects such as fatigue, depression, anxiety, weight gain, and difficulties in thinking clearly may be more troublesome.
Clonidine, an antihypertensive drug, is also used in the treatment of tics. Studies show that it is more effective in reducing motor tics than reducing vocal tics (Nass & Bressman, 2002). It is also used when treating a child with both ADHD and TS, because it is advisable to avoid the use of stimulant medications in such cases. Still, clonidine is not an innocent type of medicine. Fatigue, dry mouth, irritability, dizziness, headache, and insomnia are common side effects associated with clonidine use. Abuzzahab and Brown (2002) mention that fluphenazine and clonazepam may also be prescribed to help control tic symptoms.
When used alone, antidepressant medications are not useful in the treatment of tics. However, TS patients may develop serious depressions, and then the use of antidepressant medication should be considered. In such situations, antidepressants have been added to ongoing TS treatment (haloperidol and clonidine) with good results (Coffey et al., 1998). Complicating the assessment of depression in TS is the fact that pimozide, haloperidol, and clonidine may elicit lowered spirits or dysphoria. Therefore a trial of no medication might be considered before the addition of an antidepressant, especially if the depression emerges soon after the use of another medication and with no apparent psychosocial precipitant.
Medications are also available to treat some of the associated behavioural disorders. Stimulants such as methyphenidate, pemoline, and dextroamphetamine, usually prescribed for ADHD, although somewhat effective, have also been reported to increase tics; therefore their use is controversial (Nass & Bressman, 2002). For OCD that significantly disrupts daily functioning, fluoxetine, clomipramine, sertraline, and paroxetine may be prescribed (Coffey et al., 1998).


Medication or no medication


To date, pharmacotherapy has been considered the treatment of choice for Tourette’s disorder. On the other hand, Wilhelm et al. (2002) believe that, although psychological problems do not cause TS, psychotherapy may help the person cope better with the disorder and deal with the secondary social and emotional problems that sometimes occur. What is more, many patients refuse or discontinue medication because of unwanted side effects; others are unresponsive or suffer from residual tics despite continuing medication. Therefore, some patients with TS (especially cases with mild symptoms) prefer the use of psychotherapy instead of medication because of these side effects and also because tic symptoms tend to decrease (on their own) with age.
As some patients claim, psychotherapy has a lot to offer. One form of psychotherapy, which seems to have positive effects on patients and has become quite popular during the past few years, is behaviour therapy. Behaviour therapy is known to be safe (with no physical side effects) as well as time- and cost-effective for many behavioural disorders. However, our scientific knowledge of effective behavioural treatments for Tourette’s disorder is limited. The behavioural treatment, known as habit reversal, has become the nonpharmacological treatment of choice. Yet, it is supported by only a limited number of studies (Wilhelm et al., 2002). Azrin and Peterson (1973) reported a 93% tic reduction in a group of five patients treated with habit reversal, compared with no improvement among five patients on a waiting list. Although these results are encouraging, further research is necessary given the small number of patients studied.
Not all scientists believe that psychotherapy helps suppress the patient’s tics. They all agree on the fact though that relaxation techniques and biofeedback may be useful in alleviating stress, which can lead to an increase in tic symptoms (Cooper, Robertson & Livingston, 2003).
Despite the fact that it has not been proven that psychotherapy on its own can totally eliminate tics, it is accepted that it can be beneficial to some TS patients who require treatment of the psychological consequences of this difficult disorder. The inability to control one’s own body and even one’s own thoughts, which is taken for granted by most people, often is a great source of anxiety, guilt, fear, helplessness, anger, and depression. Some patients react by withdrawal, others by aggression, and still others by perfectionism and excessive efforts to be in control (Cooper, Robertson & Livingston, 2003). Since virtually all TS patients are subjected to some form of negative social reactions, self-esteem problems are common. In addition, the person with TS experiences all the difficulties associated with growing up with a chronic illness. For those reasons rather than for the primary symptoms of TS, psychodynamic or supportive psychotherapeutic treatment may well be indicated (Wilhelm et al., 2002).


TS, OCD, ADHD and their comorbidity. Can this suggest that TS is a Higher Executive deficit?


TS is often accompanied by features associated with obsessive compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), poor impulse control, and other behavioural problems. However, the relationships between both ADHD and TS, and OCD and TS are complex and not yet clear. Evidence is accumulating that an association exists between OCD and TS. Coffey et al. (1998) state that specific symptoms of obsessive compulsive disorder are found to be similar in TS with and without OCD and differ from tic-free OCD. This study, along with others (Robertson, 1989; Baron Cohen et al. 1994), suggests that TS with OCD constitutes a form of TS, and not of OCD, and reinforces the ideas that at least some forms of OCD are etiologically related to TS. They also suggest that TS with OCD represents a variant phenotype or maybe a more severe form of TS. At the same time, OCD alone in individuals of TS families might be considered as an alternative phenotype or could be due to reduced action of the autosomal dominant mode of inheritance of the disease. Some researchers even tend to characterise OCD as an extreme version of TS (Coffey et al., 1998).
The co-morbidity of TS and ADHD is also considered a common phenomenon. Bornstein et al. (1991) suggest that there are patients cases with TS where OCD and ADHD characteristics are being met. Should TS be considered as a frontal lobe disorder then? The answer given by scientists up to now is an indefinite one. According to the study of Baron Cohen et al. (1994) children with TS showed poor inhibition ability. Specifically, twelve-year-old children with TS showed a poor performance on a Yes-No test and on a Rapidly alternate hand positions test. They actually performed as low as four-year-olds without TS, a fact which, according to these researchers, suggests that TS should be considered as a Higher Executive Function deficit. However, Pennington and Ozonoff (1996) disagree with this statement simply because Baron Cohen et al. (1994) failed to check for the presence of OCD and ADHD across their sample (which are expected to occur in certain cases since these disorders are co-morbid). This suggests that the facts of Baron Cohen et al. (1994) study could have been caused by the co-morbid disorders and not by TS itself.
Pennington and Ozonoffs (1996) arguments are backed up by the studies of Bornstein (1991) and Ozonoff et al. (1994) which point out that children with TS (but with no other co-morbid disorders) have an average achievement on tests concerning the Higher Executive Functions. Yet, other studies (such as Channon et al., 1992) contradict these findings. So, can a definite answer be given to this question? As Pennington and Ozonoff (1996) state, further research is needed in this area. The fact that TS, OCD and ADHD are co-morbid has not been helpful in this area of research, since it has made researchers work more difficult. On the contrary it has in some cases led to misguiding results.


TS and its inheritability. Which gene(s) are we to blame?


In 1885, Gilles de la Tourette noticed that the condition now bearing his name ran in families. Now genetic make-up is thought to be a risk factor that combines with the environment to produce the disorder. Although the actual cause of TS is unknown, there is evidence that genetic factors are involved (Temple, 2003). An obvious first approach to search for responsible genes is linkage studies (such as the study of Hyde et al., 1992), but due to the complexity of the disorder (co-morbidity with other deficits), until now, results have remained elusive. Several genomic regions have been identified using linkage and association studies pointing to susceptibility loci for TS, although no clear candidate genes have yet emerged. Other regions have been excluded. Another approach is the identification and cloning of breakpoints in TS patients with chromosomal abnormalities. The advantage of this method is that when the interrupted region harbours a specific gene, this may give a direct entry into a biological pathway involved in the aetiology of TS. There is also always the possibility that the breakpoint is coincidental and has no relation to the TS phenotype. A number of candidate genes have been proposed, but none of them has yet led to the long-awaited breakthrough (Eapen, Pauls & Robertson, 1993). According to Annemieke et al. (2003), the only gene reported that was interrupted by a breakpoint is IMMP2L, the human homologue of the yeast mitochondrial inner membrane peptidase sub-unit 2; however, its role in the aetiology of TS has not been demonstrated. Candidate regions that have been indicated by chromosomal aberrations include chromosomes 9p, 7q22, 18q22, 8q22, and 7q22q31 (Annemieke et al., 2003).
It is apparent that a lot more work needs to be done so that the matter of TS inheritability is covered. Most scientists agree on the fact that genetic factors play an important role in the production of the disorder. On the other hand the question which gene(s) are we to blame after all? still remains mainly unanswered and, worst of all, findings up to now have been contradictory.


Discussion


During the past two decades a lot of issues have been covered regarding TS syndrome. On the other hand, the research that has been conducted during the past two decades has revealed new issues that need further scientific clarification. The big issue about TS that scientists are now concerned about is its treatment, since treating this disorder has always been a delicate and complex matter. Which medication is to be prescribed for this syndrome? Can a fine balance be adjusted between the benefits and side effects of each medication so the patients will not have to confront with major problems caused not by the deficit but by the treatment itself? The complexity of this syndrome and also its co-morbidity with other deficits has shown that there is still a lot that needs to be done in this area.
Moreover, can psychotherapy and methods such us behaviour therapy and biofeedback be considered an answer to TS treatment? As has been shown up to now, no matter how beneficial all these methods can be in the treatment of TS, they are still not the answer. Especially on severe TS cases, psychotherapy has proved to be helpless.
Is TS a Higher Executive dysfunction after all or not? A lot of research suggests that TS should be treated as a Higher Executive abnormality since children with this syndrome show poor performance on tasks concerning the SAS functions. Still, a lot of scientists argue that this is not the case, mainly because of the high co-morbidity of TS and other Higher Executive dysfunctions such as OCD and ADHD.
Finally there is the issue of TS inheritability. Most scientists agree on the fact that genes play an important role in the development of the disorder to a person. However, a lot more research is needed in order to specify the gene(s) which are responsible for TS. What is more, recent studies have not managed to limit down the number of candidate genes, but have actually managed instead to increase it.

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