Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 3 3 2008 09 15 100 104 Zahra Shahrivar Psychiatry and Psychology Research Center, Department of psychiatry, Tehran University of Medical Sciences, Tehran, Iran Department of psychiatry, Roozbeh hospital, Tehran University of Medical Sciences, Tehran, Iran Javad Mahmoodi Psychiatry and Psychology Research Center, Department of psychiatry, Tehran University of Medical Sciences, Tehran, Iran Ali Alavi Psychiatry and Psychology Research Center, Department of psychiatry, Tehran University of Medical Sciences, Tehran, Iran Mohammad Reza Mohammadi Psychiatry and Psychology Research Center, Department of psychiatry, Tehran University of Medical Sciences, Tehran, Iran Department of psychiatry, Roozbeh hospital, Tehran University of Medical Sciences, Tehran, Iran Mehdi Tehranidoost Psychiatry and Psychology Research Center, Department of psychiatry, Tehran University of Medical Sciences, Tehran, Iran Department of psychiatry, Roozbeh hospital, Tehran University of Medical Sciences, Tehran, Iran Soheil Saadat Trauma Research Center, Sina hospital, Tehran University of Medical Sciences, Tehran, Iran 2015 10 17 Objective: The aim of the present study was to determine the prevalence of different psychiatric disorders among 12 to 17 years old adolescents in urban areas of Tehran. Method: In this study, 1105 adolescents (12 -17 years old) were selected from 250 clusters of the entire 22 municipality areas of Tehran using a multistage sampling method. After responding to the Farsi version of the Strengths and Difficulties Questionnaire self-report version, the Farsi version of the Kiddie Schedule for Affective Disorders and Schizophrenia - Present and Lifetime version (K-SADS-PL) was administered to 273 adolescents and their families. The prevalence of adolescent psychiatric disorders was determined using the results of K-SADS-PL. Results: There were not any statistically significant differences between the sexes in the frequency of psychiatric disorders except for ADHD which was observed more frequently in boys. The most prevalent psychiatric disorderswere attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder, depressive disorders and separation anxiety disorder. Conclusion: The frequency of psychiatric disorders among the adolescents in Tehran's urban areas was comparable to the reports from other countries. However, using methods to deal with missing data makes these prevalencerates somehow higher. https://ijps.tums.ac.ir/index.php/ijps/article/view/479 https://ijps.tums.ac.ir/index.php/ijps/article/download/479/503