Tourette syndrome is a neurological condition that causes involuntary movements and sounds, but estimates of how many people have it vary wildly from 0.5 to 115 cases per 10,000 individuals. This massive difference exists because researchers use dramatically different methods to find and count patients. For example, studies that rely on hospital records report the lowest numbers because they only capture individuals with severe symptoms who actively seek medical treatment. Conversely, research conducted directly in schools reveals the highest rates of the syndrome. By relying on direct classroom observation and reports from parents and teachers, school-based studies can identify children with very mild tics who never visit a doctor. As a result, experts now recognize that Tourette syndrome is much more common than historically believed, even though pinning down exact numbers remains challenging due to mild, unrecorded cases and overlapping behavioral issues.
This review was part of my PhD dissertation. I prepared the manuscript with a colleague who came back from a scholarship in the United States. In a short time, he returned to the US to enroll to the Epidemic Intelligence Service and never came back…