Meta-analysis: Adulthood prevalence of Tourette syndrome

Tourette syndrome (TS) is estimated to have a prevalence of 0.30-0.77% in school aged children. Longitudinal studies suggest that roughly half-to-two-thirds of children with TS experience a substantial improvement in tic symptoms during adolescence. By contrast, few studies have examined adulthood prevalence of TS. Accurate prevalence estimates across the lifespan are needed to support regulatory and public health decisions.

We searched PubMED and EMBASE for studies that examined the prevalence of TS in adults. We conducted a random-effects meta-analysis of logit event rates to estimate prevalence of TS across studies. Too few studies are available to conduct moderator analysis or examine publication bias. We also examined the risk ratio of TS prevalence in adults for males compared to females.

Three studies involving 2,356,485 participants were included. There were significant differences in TS adulthood prevalence estimates between studies ranging from 49 to 657 cases of TS per million adults. Overall prevalence of TS in adulthood was estimated to be 118 cases of TS per million adults (95%CI: 19-751 cases per million adults). There was a large amount of heterogeneity between studies (I² = 99%) that was likely related to differences in their methods of identification of TS cases. By contrast, the male:female ratio of risk of adulthood TS was similar between studies with a Risk Ratio = 2.33 (95% CI: 1.72-3.16).

Estimates of adulthood prevalence of TS are sparse and likely highly affected by differences in method of case identification. Diagnosis and diagnostic estimates of TS could be aided by including a requirement for impairment as well as potential remission criteria similar to other psychiatric conditions.