en اپيدميولوژي Epidemiology پژوهشي Original Article <p style="text-align: justify;">Background and purpose: The age of the onset of obsessive-compulsive disorder (OCD) and its&nbsp;manifestation is now identified at childhood. In the present study, we aimed to&nbsp;epidemiologically assess OCD and its main determinants in school-age children.&nbsp;</p> <p style="text-align: justify;">Materials and Methods: This cross-sectional study was performed on 600 consecutive schoolage children (7-12 years old) in primary schools at Kermanshah, Iran in May 2012. OCD status was assessed using the Maudsley Obsessive Compulsive Inventory.</p> <p style="text-align: justify;">Results: In this study, the prevalence of OCD in children were 12.2% (73 person). Among&nbsp;OCDs, 32.0% were male and 68.0% were female with a significant difference (P < 0.001).&nbsp;Among different subscales of OCD, checking was more prevalent in girls than in boys (74.0%&nbsp;vs. 65.0%, P < 0.001), whereas doubting was more revealed in boys than in girls (56.0% vs.&nbsp;34.0%, P < 0.001). In this regard, no differences were found between boys and girls in the rate&nbsp;of washing subscale (43.0% vs. 40.0%, P = 0.456) and slowness domain (30.0% vs. 34.0%,&nbsp;P = 0.294). Totally, mean MOCI score was significantly a higher in girls than in boys in&nbsp;different grades of education. OCD was influenced by father&rsquo;s occupation status, parents&rsquo;&nbsp;education level, order of birth, dependence to mothers and previous history of OCD in fathers.<br> Conclusion: The prevalence of OCD was a higher than other areas in the country and other&nbsp;populations. Because of the existence of OCD potential determinants including socioeconomic&nbsp;level and familial tendency, the high prevalence of the disease must be considered in correlation&nbsp;with these factors.</p> Obsessive-Compulsive Disorder, Children, School, Age Determinant 1 7 http://jhs.mazums.ac.ir/browse.php?a_code=A-10-503-2&slc_lang=en&sid=1 Marzieh Assareh 10031947532846004926 10031947532846004926 No Department of Child and Adolescent Psychiatrist, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran Reza Tabrizi 10031947532846004927 10031947532846004927 No Health Policy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran Mahboubeh Firouzkouhi-Moghaddam 10031947532846004928 10031947532846004928 No Department of Child and Adolescent Psychiatry, Research Center for Children and Adolescents Health, Zahedan University Tayebeh Rakhshani trakhshani@gmail.cim 10031947532846004929 10031947532846004929 Yes epartment of Public Health, School of Health AND Research Center for Health Sciences, Shiraz University of Medical sciences