OBJECTIVETo assess the prevalence of depressive symptoms, trends on its longitudinal development and related influencing factors among primary and middle school students in Changfeng county of Anhui province.

METHODSThrough cluster sampling methods, all students from 3 to 9 grades in 5 primary schools and 3 middle schools in Changfeng county of Anhui province were investigated through questionnaire as subjects of baseline survey in December 2009. Subjects of this longitudinal study were students in grades 3, 4 and 7 at the time of the baseline survey and were contacted once a year for two years. At last, a total of 816 students participated in all the three surveys. A structured questionnaire including Children's Depression Inventory, socio-demographic characteristics and some potential influential factors was employed for this study. A Generalized Estimating Equation (GEE) was used to evaluate the related influencing factors of children's depressive symptoms in the longitudinal study.

RESULTSPrevalence rates of depressive symptoms were 11.3% , 10.4% and 8.5% , respectively, at the baseline, 1-year and 2-year follow-up studies, among primary and middle school students. Scores on depressive symptoms of total subjects and children who had always been left at home in the follow-up process showed significant differences at the three surveys (F = 13.423, P < 0.001; F = 5.761, P = 0.003). 25 percent of the 92 students who showed depressive symptoms at the baseline survey remained those depressive symptoms at the 1-year follow-up study and 87 percent of the 23 students who had depressive symptoms at the baseline and 1-year follow-up surveys still showing depressive symptoms at the 2-year follow-up study. Results from the GEE program indicated that grade 3 students, having syblings, family with dysfunction or at low level of self-esteem etc., were prone to development while sex and parents' educational level were not correlated with depressive symptoms.

CONCLUSIONPrevalence of depressive symptoms among primary and middle school students in Changfeng county of Anhui province appeared a decreasing tendency during the follow-up process in our study. Through the longitudinal development, we noticed that the prevalence of depressive symptoms seemed to be related to the personal characteristics, education and family environment of the subjects under our study. Improving the level of family function as well as individual's self-esteem might positively contribute to mental health of those primary and middle school students.