[Epidemiological survey of psychiatric disorders in Japanese school children. Part III: Prevalence of psychiatric disorders in junior high school children].

In order to determine the prevalence of psychiatric disorders in junior high school children, an epidemiological survey of Japanese regular public junior high school children was conducted using Rutter's questionnaire method for screening and a diagnostic interview by pediatricians for the final diagnosis. Both teacher's and parent's questionnaires by Rutter were utilized. Two pediatricians carried out semi-structured interviews of 10-12 minutes for every child and diagnosed their mental state. In part 1 (previously reported), the Japanese version of Rutter's questionnaires was found to be satisfactory for screening, and the diagnostic interview used in this survey was shown to be a reliable tool for the diagnosis of psychiatric disorders of the adolescent. In part 2, the prevalence of psychiatric disorders was studied in the 592 school children who were the subject of the preliminary survey. In the present study, a total of 1,992 children from 5 junior high schools in Gunma prefecture were surveyed cross-sectionally of whom 1,672 (84.3%) screened negative, and 312 (15.7%) positive. The positives and a part of the negatives were randomly selected for interviews, and were diagnosed as to whether they have psychiatric disorders or not by the criteria of Rutter. The overall prevalence rate of diagnosed psychiatric disorders in these school children was 14.8%, (20.1% for males and 8.3% for females). The prevalence rate is significantly higher in males than in females. Disorders diagnosed were classified into emotional, conduct, and mixed disorder, based on Rutter's classification. No cases of schizophrenia and anorexia nervosa were found here as well as in the preliminary survey. The ratio of emotional to conduct disorders was 1.9. Prevalence of conduct disorder in females was one seventh that in males. This study also revealed that the questionnaire method is effective for screening for psychiatric disorders in children, but is not sufficient for differentiating types of disorders. Therefore the diagnostic interview was shown to be useful not only for epidemiological surveys but also for mental health services.