Coimbra University, Portugal

Comorbidities of Tourette's syndrome

“Tourette's syndrome and associated disorders: a systematic review”, posted 8 October 2013 by Bárbara Roque Ferreira, José Luís Pio Abreu and Cristina Januário. Medical Faculty of the Coimbra University, Portugal.

Introduction
Tourette’s syndrome is the most common cause of tics and it is clinically heterogeneous. Because of that heterogeneity, many cases may remain underdiagnosed or not very well accompanied. Indeed, at least 90% of these patients may have other comorbidities, mainly neuropsychiatric, and we frequently see that the number of comorbidities is positively correlated with the severity. Thus, when we treat these patients, it is important to consider the presence of other associated disorders in order to choose the better treatment for each case.

Our article is a systematic and updated review of all the comorbidities of Tourette’s syndrome. As far as we know, in the scientific literature, there is no other article which globally analysis all the disorders associated with this syndrome. We point out the prevalence of those disorders and the clinical features we may find when we look at these patients.
Moreover, in this article, we also analyze the proposals to explain why Tourette’s syndrome is associated with so many neuropsychiatric disorders. We know Tourette's syndrome is in the interface between Neurology and Psychiatry and the neurosciences have clarified several psychiatric disorders. Therefore, we also think this study can amplify our understanding about Tourette’s syndrome and other psychiatric disorders.

Abstract
Objective: Compile data on Tourette’s syndrome, tics and associated disorders. Methods: A systematic review of the literature was conducted, using the ‘‘5S’’ levels of organization of evidence from healthcare research (Systems, Summaries, Synopses, Syntheses, Studies), based on the model proposed by Haynes. We used the keywords “Tourette”, “tics” and “comorbidity” and we cross-referenced them. We have also included the articles supplied by the Publisher and in process on July 31, 2013. Results: From all the articles given by the research, we selected 65 for relevance, since those analyzed the epidemiology, the clinical features and the etiopathogeny of Tourette’s syndrome and its comorbidities. Tourette’s syndrome is included in the hyperkinetic movement disorders and at least 90% of patients exhibit neuropsychiatric comorbidities of which attention deficit hyperactivity and obsessive-compulsive disorders are the most common. The syndrome is clinically heterogeneous and has been understood as a dysfunction in cortico-striatal-thalamic-cortical circuits involving various neurotransmitters. Although the genetic etiology has been widely studied, other factors are also important to better understand this syndrome and the associated disorders. Conclusions: Tourette’s syndrome is a neurodevelopmental disorder which results from the impact of stress factors on a vulnerable biological substrate, during the critical periods of the neurodevelopment. The study of Tourette’s syndrome and its comorbidities may clarify at different levels our understanding of several neuropsychiatric disorders with clinical and therapeutic relevance.

Author's credentials 

1. Bárbara Roque Ferreira

  • Medical Doctor, Coimbra Hospital and University Centre, Portugal. 
  • Master in Medicine, Medical Faculty of Coimbra University, Portugal. Master’s thesis in the area of Tourette’s syndrome.
  • Member of the Portuguese Medical Association.
  • Some scientific publications and academic awards. One book published in Portugal. 

2. José Luís Pio Abreu 

  • MD, PhD, psychiatrist, professor of Psychiatry at Medical Faculty, Coimbra University, Portugal.
  • Member of the Centro de Filosofia Das Ciências, Lisbon University.
  • Nine books published in Portugal, some of them also published in Brazil, Italy, Spain and Latin America. Three of them awarded in Portugal and in Italy.
  • A long career of research and publishing since 1972.
  • More recent papers in Acta Psychiatrica Scandinavia, British Journal of Psychiatry, Revista Brasileira de Psiquiatria, Australian and New-Zealand Journal of Psychiatry, European Psychiatry, Journal of Trauma and Dissociation. 

3. Cristina Januário

  • MD, PhD, neurologist, Coimbra Hospital and Universitary Centre (CHUC EPE), Neurology Department, Coimbra, Portugal. 
  • Head of Department of the Movement Disorder’s Unit. Ataxia and Movement Disorders specialist. 
  • Assistant Professor of Neurology, Medical Faculty, Coimbra University, Portugal. Assistant Professor of Biochemistry, Medical Faculty, Coimbra University, Portugal (1989-1998).
  • A long career of research in the area of movement disorders (e.g. “LRRK2 role on auto-antibody production by human B cells”, Co-PI: Margarida Carneiro, Cristina Januário, Rosário Almeida; Michael J. Fox Foundation for Parkinson’s).
  • Several funded projects in the movement disorders. (e.g. “Enroll-HD: A Prospective Registry Study in a Global Huntington’s Disease Cohort.” A CHDI Foundation Project. PI Cristina Januário; “Everyday Executive Function in Parkinson and Huntington Disease: a Novel Ecological Approach”, supported by FCT - SFRH/BD/85358/2012). 

Contact the authors.