History of Tourette syndrome

Tourette syndrome is an inherited neurological disorder with onset in childhood, characterized by the presence of multiple physical (motor) tics and at least one vocal (phonic) tic.^[1]

The eponym was bestowed by Jean-Martin Charcot (1825–93) on behalf of his resident, Georges Albert Édouard Brutus Gilles de la Tourette (1859–1904), a French physician and neurologist, who published an account of nine patients with Tourette's in 1885. The possibility that movement disorders, including Tourette syndrome, might have an organic origin was raised when an encephalitis epidemic from 1918–1926 led to a subsequent epidemic of tic disorders. Research in 1972 advanced the argument that Tourette's is a neurological, rather than psychological, disorder; since the 1990s, a more neutral view of Tourette's has emerged, in which biological vulnerability and adverse environmental events are seen to interact.

Findings since 1999 have advanced TS science in the areas of genetics, neuroimaging, neurophysiology, and neuropathology. Questions remain regarding how best to classify Tourette syndrome, and how closely Tourette's is related to other movement disorders or psychiatric disorders. Good epidemiologic data is still lacking, and available treatments are not risk free and not always well tolerated.

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Nineteenth century

  A French doctor, Jean Marc Gaspard Itard, reported the first case of Tourette syndrome in 1825,^[2] describing Marquise de Dampierre, an important woman of nobility in her time.^[3] Jean-Martin Charcot, an influential French physician, assigned his resident Georges Albert Édouard Brutus Gilles de la Tourette, a French physician and neurologist, to study patients at the Salpêtrière Hospital, with the goal of defining an illness distinct from hysteria and from chorea. Charcot and Tourette believed that the "tic illness" they had observed was an untreatable, chronic, and progressive hereditary condition.^[4]

In 1885, Gilles de la Tourette published an account of nine patients, Study of a Nervous Affliction, concluding that a new clinical category should be defined.^[5] His description included accounts of Marquise de Dampierre, previously described by Itard, as a reclusive aristocratic lady who "ticked and blasphemed" from the age of seven until her death at the age of 80 years. Gilles de la Tourette describes the common feature of involuntary movements or tics in all nine patients. The eponym was later bestowed by Charcot after and on behalf of Gilles de la Tourette.^[4][6]

Little progress was made over the next century in explaining or treating tics. With limited clinical experience, involving typically one or two patients, authors advanced different ideas, including brain lesions similar to those resulting from rheumatic chorea or encephalitis lethargica as a cause of tics, faulty mechanisms of normal habit formation, and treatment with Freudian psychoanalysis. The psychogenic view prevailed well into the 20th century.^[4]

Twentieth century

The possibility that movement disorders, including Tourette syndrome, might have an organic origin was raised when an encephalitis epidemic from 1918–1926 led to a subsequent epidemic of tic disorders. The psychoanalytic theory was so dominant that it was claimed that an organic component alone would not be sufficient to produce Tourette syndrome. At the time, psychiatrists believed patients with tics must also be suffering from unresolved psychological disturbances or psychosexual conflicts, and psychiatric intervention was the preferred method of treatment. Patients and their families were told that their own psychological maladjustments were to blame for their symptoms, adding to the burden carried by the patients and their families. Until the early 1970s, psychoanalysis was the preferred intervention for Tourette syndrome.^[7]

During the 1960s and 1970s, as the beneficial effects of haloperidol (Haldol) on tics became known, the psychoanalytic approach to Tourette syndrome was questioned. The first description of haloperidol in the treatment of Tourette's was published by Seignot in 1961.^[8] The turning point came in 1965, when Arthur K. Shapiro—described as "the father of modern tic disorder research"^[9]—treated a Tourette’s patient with haloperidol. Dr. Shapiro and his wife, Elaine Shapiro (PhD), reported the treatment in a 1968 article, and severely criticized the psychoanalytic approach.^[7]

The Shapiros, working with the patient families who founded the Tourette Syndrome Association (TSA) in 1972, advanced the argument that Tourette's is a neurological, rather than psychological, disorder,^[7] and worked to persuade the media to promote information about Tourette's. The U.S. National Institutes of Health (NIH) turned down a 1972 grant proposal from the TSA because "the reviewers believed there were probably no more than 100 cases of TS in the entire nation".^[10] Subsequent articles on Tourette's in Good Housekeeping, The New York Times and Ann Landers produced an "enormous response, proving that there were many undiagnosed cases of TS across the United States".^[10]

Since the 1990s, a more neutral view of Tourette's has emerged, in which biological vulnerability and adverse environmental events are seen to interact.^[11][4] In 2000, the American Psychiatric Association published the DSM-IV-TR, revising the text of DSM-IV to no longer require that symptoms of tic disorders cause distress or impair functioning.^[12]

Contemporary

As of 2006, the Tourette Syndrome Association has contacts in more than 50 countries.^[13] The Tourette syndrome International database Consortium (TIC) brought together data on clinical samples of patients with Tourette syndrome from twenty-two countries (Argentina, Australia, Austria, Belgium, Brazil, Canada, Denmark, Germany, Hungary, Iceland, Israel, Italy, Japan, The Netherlands, Norway, Peoples Republic of China, Poland, South Africa, Sweden, Turkey, the US and the UK);^[14] Tourette's has also been studied in Chile, Colombia, Costa Rica, India, Indonesia, Korea, and Spain.^[15]

Research directions and controversies

Findings reported in published studies of Tourette syndrome since 1999 have advanced TS science in the areas of genetics, neuroimaging, neurophysiology, and neuropathology. The TSA supports a clinical database that may help identify genes involved in Tourette syndrome, and the TSA International Genetic Consortium has collected a database on large extended families for future studies. Novel neuroimaging studies are being employed to study tic expression and functional or cognitive deficits in TS patients. Studies of Tourette's neurophysiology and neuropathology are attempting to link deficits in Tourette's to specific brain mechanisms, and have taken advantage of a brain bank sponsored by the TSA. Clinical trials have focused on understanding tic suppression, comorbid conditions, novel treatment approaches such as botulinum toxin, and targeted behavioral therapies. Controversy remains in the areas of deep brain stimulation and PANDAS.^[16]

Questions remain regarding how best to classify Tourette syndrome, and how closely Tourette's is related to other movement disorders or psychiatric disorders. Good epidemiologic data is still lacking, and available treatments are not risk free and not always well tolerated.^[16]

The direction of current and future research in Tourette's was outlined in a 2005 journal article^[17] by the outgoing chairman of the TSA Scientific Advisory Board. Swerdlow divides the research landscape into five broad questions about Tourette's: what is it, who has it, what causes it, how it should be studied, and how it should be (medically) treated.

According to Swerdlow,^[17] "the 'core' TS conundrum" is a lack of consensus about the definition of Tourette syndrome. Since vocal tics result from a "motor event (ie, a contracting diaphragm moving air through the upper airways)", TS could be defined as a disorder of motor tics, eliminating the distinction between TS and the other tic disorders. Individuals who have only tics may not be functionally impaired, raising the question of whether Tourette's as currently defined should be a DSM diagnosis. Swerdlow highlights the importance of studies in new areas such as behavioral techniques, and says that "the whole-cloth dismissal of psychologic forces in the pathobiology of TS was a strategic error". Questions remain about whether co-occurring (comorbid) conditions should be part of the core definition, and why sensory phenomena, which are a core part of Tourette's, are not part of the diagnostic criteria.

Dropping the criteria for impairment from the diagnosis resulted in higher estimates of the prevalence of TS (the question of "who has it?"). Older estimates "came from tertiary referral samples, the sickest of the sick"; greater prevalence casts the condition in an entirely new light, and calls for new biological models of the condition and new approaches to addressing a more common disorder.^[17] Discovering the causes of Tourette's may help resolve the questions of what it is and who has it. The autosomal dominant inheritance model has not been validated, and past research has been affected by the problem of referred samples, which may not reflect broader populations of persons with Tourette's. Probabilistic genetic models may yield better clues than the "one gene equals one disorder" approach. One of the most controversial presumed causes, the PANDAS hypothesis, has sparked disagreement.^[17]

Expanding criteria for the diagnosis, and increasing awareness of the impact of comorbid diagnoses, has resulted in further questions of how to study Tourette's. Tourette's patients are often recruited from sources that introduce ascertainment bias towards one 'type' of TS. Developing and applying standardized instruments, along with a greater awareness of ascertainment bias in recruitment sources, will be important in genetic studies. We do not know if "we lose both signals and are just adding noise to the experimental outcome"^[17] when comorbid conditions, such as OCD or ADHD, are included or excluded from study samples, or samples include/exclude children or adults, or patients with severe symptoms.

Tourette's is a heterogeneous condition, with waxing and waning symptoms. The inherently changing nature of its core symptoms complicates research design, resulting in questions about medications in clinical practice. Results from case studies may not be borne out by controlled or prospective, longitudinal studies, stimulants may be underused, and behavioral therapies are understudied. High-profile media coverage focuses on treatments that do not have established safety or efficacy e.g., deep brain stimulation, and alternative therapies involving unstudied efficacy and side effects are pursued by many parents.^[17]

In the USA, the NIH has ongoing clinical trials,^[18] and the TSA funds ongoing research through its Research Program and Research Grant Awards.^[19] Other worldwide ongoing trials can be found by contacting Tourette syndrome advocacy groups.^[20]

Notes

References

• Kushner, HI. A cursing brain?: The histories of Tourette syndrome. Harvard University Press, 2000. ISBN 0-674-00386-1