To assess the prevalence of obsessive compulsive symptoms OCS among adolescents, the prevalence of OCD among adolescents and as a secondary aim to assess recurrent tonsillitis among adolescents with OCS and OCD.

Consent from the Directory of Ministry of Education and another consent from the General authority of Population for the questionnaire and procedures were taken. The study is a cross sectional carried on 1299 secondary school students, the sample size was chosen based on an estimated OCD prevalence of 2% in literature. Equal samples were recruited from the 3 educative zones in Alexandria Governorate. Obsessive compulsive symptoms were assessed by the Arabic version of Lyeton obsessive inventory child version LOI-CV. Students scoring above 35 were subjected to the Mini International Neuropsychiatric Interview for children MINI-KID Arabic version to assess psychiatric comorbidities. OCD patient students detected by MINI-KID were assessed by psychiatric interview to confirm fulfilling criteria of OCD according to DSM IV -TR criteria.Recurrent tonsillitis was assessed by a standardized questionnaire for parents to assess if no recurrent tonsillitis or if there's recurrent tonsillitis including those who had tonsillectomy or receiving long acting penicillin injection.

The prevalence of obsessive compulsive symptoms was 15.5%, while that of obsessive compulsive disorder was 2.2%. As for history of recurrent tonsillitis, no difference could be found between those having OCD and the other group non-OCD with ob sessive compulsive symptoms (X2 = 0.87; p > 0.05).