Tourette Syndrome and Tic Disorders in a Swedish School Population Prevalence, Clinical Assessment, Background, Psychopathology, and Cognitive Function
Abstract: A total population of 4,479 children (7-15 years of age) attended school in Ludvika & Smedjebacken in 2000. All the school children and their parents were asked to fill in a questionnaire concerning different tics A three-stage procedure was used: tic identification, interview, and clinical assessment.Tourette syndrome, according to DSM IV criteria was found in 25 (0.6%) of the children, another 34 (0.8%) suffered from chronic motor tics (CMT), 24 (0.4%) from chronic vocal tics (CVT) and 214 (4.8%) children had had transient tics (TT) during the last year. Altogether 297 (6.6%) children had or had had some tic disorder.Twenty-five controls without tics and 25 children with TT of the same age, sex and school as the TS children were randomly chosen. They were together with the 34 children with CMT and the 24 children with CVT examined with use of a broad battery of instruments.The mean age of the first symptoms of TS was significantly lower than the onset of chronic motor/vocal tics. A younger age of onset of TS indicated more severe tics. Eighty per cent had a first-degree relative with a psychiatric disorder such as tic disorder, obsessive-compulsive behaviour, attentiondeficit/hyperactivity disorder (ADHD), or depression. A non-significant increase with regard to reduced optimality score in the pre-, peri-, or neonatal periods was found in children with TS compared to controls. No differences were found concerning socio-economic status. Psychiatric comorbid disorders were found in 92% of the children with TS. ADHD was most common. Patterns of psychiatric comorbidity were similar in children with TS and CVT. Children with TS perform poorer than the population in general with respect to cognitive functioning and self-perception.The results are discussed as they relate to the need for case identification, diagnosis, intervention, and treatment.
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