Objective: With respect to the importance of Mental health and Passing school years where such mental bealth develops. We decided to study such prevalence of obsessive – compulsive disorder (OCD) in the adolescents of middle school stage as the situational analysis as one of their the most important indicator of their mental health. Also we studied such relating variables of factors a age, gender, educational status of parents, number of siblings and birth order.

Meterials & Methods: In this cross – sectional study Six hundreds seventy two (672) students of middle school of Tehran (369 girls and 303 boys) withing age range of 11-15 yrs old were selected. With multi-stage sampling method we considered four regions of educational offices of Tehran in North, South, West and East. Each regions were selected to have two middle schools (one for girls and the other for boys) and in each of schools we selected two or more classes from different stages. Finally the students of each classes answered the SCL-90R questionnair which subsequently data were gathered. 

Results: Considering mean score of questions related to OCD in SCL-90R questionnair, the prevalence of OCD found to be 10.8% (CI 95%: 8.3%-13.2%). There were not a significant difference between boys (8.7%) and girls (12.3%). Age and geographic region of school had significant correlation with prevalence of OCD. With increasing the age, the prevalence of OCD also increased East and South regions, The prevalences were more than the other regions. The most co-morbidty comorbidity was generalized anxiety disorder (GAD). Value of P<0.05 was found as the significance of differences in all measurments.

Conclusion: The relatively high prevalence of OCD in this study lead us to increase attention to mental health programs at schools, especially training the students and teachers to promote their referrals while facing new susbpected cases. This will ease further early propper diagnosis and firmative Treatments.