To Örebro University

BACKGROUND: It is unknown whether individuals with tic disorders are at increased risk for serious transport accidents.

OBJECTIVES: The aim of this study was to investigate the risk for injuries or death caused by transport and motor vehicle accidents in individuals with Tourette syndrome or chronic tic disorder.

METHODS: This population-based, sibling-controlled cohort study included all individuals aged ≥18 years living in Sweden between 1997 and 2013 (N = 6,127,290). A total of 3449 individuals had a registered diagnosis of Tourette syndrome or chronic tic disorder in the Swedish National Patient Register. We also identified 2191 families with full siblings discordant for tic disorders. Cox proportional hazards regression modeling was used to estimate the risk for injuries or deaths as a result of transport accidents in individuals with a lifetime diagnosis of Tourette syndrome or chronic tic disorder compared with unexposed individuals and siblings.

RESULTS: Individuals with tic disorders had a higher risk for transport injuries or death compared with the general population (adjusted hazard ratio, 1.50 [95% confidence interval: 1.33-1.69]) and their unaffected siblings (adjusted hazard ratio, 1.41 [95% confidence interval: 1.18-1.68]). The risks were similar across sexes. The exclusion of most psychiatric comorbidities did not alter the magnitude of the estimates. However, the risks were no longer significant after exclusion of individuals with comorbid attention deficit hyperactivity disorder.

CONCLUSIONS: The marginally increased risk for serious transport accidents in tic disorders is mainly driven by attention deficit hyperactivity disorder comorbidity. Improved detection and management of attention deficit hyperactivity disorder symptoms in this patient group are warranted.