Objective  To understand the prevalence of depressive symptoms in middle school students in Yuyao, of Zhejiang province, identify the influencing factors and provide evidence for the development of psychological intervention measures to promote the mental health of middle school students.

  Methods  A questionnaire survey was conducted in the students selected through stratified cluster sampling from 2 junior high schools, 2 senior high schools and 1 vocational and technical school in Yuyao. The depression symptoms were assessed by CES-D, and the influencing factors of depression were identified by Poisson regression analysis.

  Results  A total of 1 378 questionnaires were distributed and 1 374 were returned, with an effective response rate of 99.71%. The score of CES-D was (12.95±4.76) and the detection rate of depressive symptom was 17.90%. The positive rate in girl students (21.53%) was higher than that in boy students (14.37%), the difference was not significant (P>0.05). There were no significant differences in the detection rate of depressive symptom among different grades (P>0.05). The results of Poisson regression analysis showed that being girl student (OR=1.465), living in town (OR=1.450), living in school (OR=3.498), having been beaten and scolded by parents in the past 30 days (OR=1.795) , school suspension due to illness in the past year (OR=3.031), having been seriously injured in the past year (OR=3.177), having been bullied in school in the past 30 days (OR=2.133) and Internet addiction (OR=1.747) were the risk factors for depressive symptoms. Conclusion The prevalence rate of depressive symptoms in middle school students in Yuyao was 17.90%. It is necessary to pay close attention to mental health of middle school students, and to develop scientific and effective psychological intervention measures.