Objectives: Tourette syndrome is a disease with vocal and motor tics. This disorder is co-morbid with many psychiatric disorders, among which obsessive-compulsive disorder is the most common.

Methods: During a one-year period, 30 patients with Tourette disorder were studied at an adolescent psychiatry referral clinic. It was an analytical-descriptive study. Subjects were selected by convenience sampling. The control group was selected from students in Tehran schools similar to the first group in terms of age and gender. K-SADS questionnaire was used to examine the existence of obsessive-compulsive disorder in both groups. The results were analyzed with SPSS software. Results: The apparent co-morbidity of obsessive-compulsive disorder and Tourette syndrome was seen in this study, such that 53% of patients affected with it had obsessive-compulsive disorder. Statistics obtained was higher compared to earlier data. Although this co-morbidity was somewhat different in the two genders, it was not considered statistically significant (80% girls and 48% boys).

Discussion: More focus should be laid upon the co-morbidity between Tourette and OCD. It is recommended to study patients with Tourette syndromemore extensively in terms of co-morbidity with other psychiatric disorders, especially the obsessive-compulsive disorder.