Increased risk of epilepsy in children with Tourette syndrome: A population-based case-control study.

The association between epilepsy and Tourette syndrome has rarely been investigated. In this retrospective cohort study, we analyzed a dataset of 1,000,000 randomly sampled individuals from the Taiwan National Health Insurance Research Database to determine the risk of epilepsy in children with Tourette syndrome. The study cohort consisted of 1062 patients with Tourette syndrome aged ≤ 18 years, and the control group consisted of three times the number of age- and sex-matched patients without Tourette syndrome, who were insurants, from the same database during the same period. The Tourette syndrome group had an 18.38-fold increased risk of epilepsy than the control group [hazard ratio=18.38, 95% confidence interval (CI)=8.26-40.92; P<0.001]. Even after adjusting for the comorbidities, the risk of epilepsy in the Tourette syndrome group with comorbidities remained high (hazard ratio=16.27, 95% CI=6.26-18.46; P<0.001), indicating that the increased risk was not associated with comorbidities. This population-based retrospective cohort study provides the first and strong evidence that Tourette syndrome is associated with a higher risk of epilepsy. A close follow-up of children with Tourette syndrome for the development of epilepsy is warranted.