Objective: To estimate the prevalence and to describe clinical characteristics of tic disorders in 12-15 year old Warsaw schoolchildren.
Method: Children attending 24 randomly selected schools were screened by inquiring their parents and teachers. Children indicated as tic-positive by the screening procedure were investigated using semi-structured questionnaires and the Polish version of YGTSS scale. A validity study involved random selection and investigation of 130 non-indicated subjects.
Results: Out of 1,579 screened children, 104 met criteria for tic disorders, giving a lifetime prevalence of 9.9% (95% CI 7.1-12.6%) and a point prevalence of 6.7% (4.3-9.1%). Lifetime prevalence of ICD-10 tic disorders was 2.6% (95% CI 1.2-4.1%) for transient tic disorder (TTD); 3.7% (1.9-5.4%) for chronic tic disorder (CTD); 0.6% (0.2-0.9%) for Tourette disorder (TD); and 2.9% (1.2-4.6%) for non-specific tic disorder. Screening procedure had high sensitivity (92%) and low positive predictive value (18%).
Conclusion: Tic disorders are common among Warsaw schoolchildren, have mild severity and form a continuum. The present study has confirmed numerous problems with studying neurobehavioral disorders in general population not referred to physicians, and stressed out the need to improve education on tic disorders in the general public.