Course of Tourette Syndrome and Comorbidities in a Large Prospective Clinical Study

27.04.2017 11:17:00

 

 

 

     Tourette Syndrome could be defined as a childhood-onset neurodevelopmental disorder characterized by tics (vocal, motor) which indicates a progress for more than 1 year. Recently, the prevalence of  Tourette Syndrome has been estimated as approximately 0.8% among children and adolescents. Boys (ratio 3-4:1) are mainly influenced by Tourette Syndrome. The symptoms of Tourette Syndrome reveal itself usually at age 4 to 6 years as mild motor tics, followed by more complex motor and vocal tics and peaking in severity between the ages of 10 and 12 years and following as ascending and descending way.

 

     Only 8% to 14%  of  Tourette Syndrome population constitutes pure Tourette Syndrome diagnosis. Tourette Syndrome is often associated with comorbidities and coexistent psychopathologies such as obsessive-compulsive disorder (OCD) (prevalence of 36% to 50%) and attention-deficit/hyperactivity disorder (ADHD) (50% to 60%) as most frequently seen. Moreover, depression, anxiety, and personality and conduct disorders are also counted as coexisting psychopathologies. Also, the prevalence of autism spectrum disorder (ASD) is higher  in individuals diagnosed with Tourette Syndrome. However, among all these potential comorbidities, the burden of OCD and ADHD have an earlier onset than tics and significant negative influence on morbidity and also quality of life. Moreover, ADHD differs from tics in terms of earlier onset and later decline.

 

     So, this prospective study, which is published by Journal of the American Academy of Child and Adolescent Psychiatry, aims to examine clinical course of tics and comorbidities during adolescence and the prevalence of coexisting psychopathologies. Specifically, an age-related tic decline as well as a Tourette Syndrome associated ADHD symptoms decline were expected, but obsessive-compulsive disorder (OCD) and subclinical ADHD symptoms still continue. The study was conducted in two phases: during the periods 2005 to 2007 (T1) and 2011 to 2013 (T2). All participants completed a standardized (as Rating Scales) and comprehensive (as based on DSM-IV) examination assessing comorbidities; OCD, ADHD, intermittent explosive disorder , and sleep disturbance at both T1 and T2. To provide a better evaluation, coexistent psychopathologies were examined also with additional measurements (The development and Well-Being Assessment (DAWBA)) and neuropsychological tests. Furthermore, If this evaluation results were more than 6 months after T2, the rating of tics was repeated as T2+ condition.

 

     According to results of the follow up assessments (T1, T2, T2+), the severity of tics is on the decline yearly during adolescence. 17.7% of participants above 16 years had no tics, 59.5% of participants had minimal or mild tics, and 22.8% had moderate or severe tics. Also, the severity of both OCD and ADHD declined yearly. At follow-up part, 63% of participants had comorbidities or coexistent psychopathologies and only 37% of participants had pure Tourette Syndrome. In conclusion, age-related decline in tics and ADHD symptoms (symptoms of inattention, hyperactivity, and impulsivity) and also a decline in the severity of OCD during adolescence were indicated. On the other hand, sleep disturbance increased significantly with age. Moreover, some OCD symptoms were preserved and ADHD norm analysis confirmed that problems (executive difficulties in daily life like planning, education and relating to their peers) continued in spite of significantly decline of severity. In addition, all these findings provide a clinical attention and an evidence for clinicians to advise their patients concerning clinical course of tics and comorbidities.

 

 

 

 

 

Reference:

Debes N. M., Groth C., Lange T., Rask C. U., Skov L. (2017). Course of Tourette Syndrome and Comorbidities in a Large Prospective Clinical Study, J Am Acad Child Adolesc Psychiatry 2017;56(4):304-312.

 

 

 

 

 

 

 

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