Prevalence of tic disorders among Warsaw schoolchildren

My first project, completed with a nice team of medical students during 1998-1999. In the first stage, we asked parents and teachers of 1579 children 11-12 years old attending 24 randomly selected schools, whether pupils have involuntary movements or emit unvoluntary sounds. In the second stage, we interviewed all children indicated as having involuntary movements, for evidence of tic disorders and concomitant conditions. We found that 10% of children have had tic disorders in their life, but most of them were of short duration. It was my first major study which resulted in a doctoral thesis in 2003, three peer-reviewed publications and some conference presentations.