Objective: To learn the status of internet addiction and its influencing factors among junior high school students in Shapingba District of Chongqing,providing basis for intervention measures. Methods: From December 2018 to January 2019,all the students in four middle schools in Shapingba District of Chongqing were selected by cluster sampling method,and investigated the status of internet addiction,family background and so on by a designed questionnaire. The influencing factors for internet addiction were analyzed by multivariate logistic regression model. Results: A total of 2 922 questionnaires were sent out and 2 825 valid ones （96.68%） were recovered. The prevalence rate of internet addiction was 9.49% （268 cases）. The Results of multivariate logistic regression analysis showed that senior students （Grade 8,OR=1.764,95%CI：1.284-2.438;Grade 9,OR=1.822,95%CI：1.301-2.561）,living on campus （OR=1.550, 95%CI： 1.170-2.042）,authoritarian parenting style （OR=2.180,95%CI： 1.624-2.914）,neglecting parenting style （OR=3.974,95%CI：2.308-6.619）,watching TV more than two hours per day （OR=1.880,95%CI：1.432-2.458） and unlimited time on watching electronic screen （OR=1.952,95%CI：1.498-2.539） were risk factors for internet addiction. Conclusions The prevalence rate of internet addiction was 9.49% among junior high school students in Shapingba District. Grade,accommodation,parenting style,time spent daily on watching TV and restriction on watching electronic screen were the influencing factors.

Objective: To explore the relationship between pubertal status, pubertal KAP and adolescents quality of life and the moderating effect of pubertal KAP between pubertal status and quality of life, and to provide a reference for making measures to improve adolescents quality of life. Methods: A descriptive cross-sectional study design which recruited 6 746 adolescents in two districts of Chongqing with cluster sampling was applied. Data was collected by Adolescent Quality of Life Scale developed by our team, Pubertal Development Scale(PDS) from Petersen and Crockett, self-designed KAP questionnaire and basic situation questionnaire. Results: The early puberty, mid-puberty and late puberty suffered lower physical, psychological and total quality of life than the pre-pubertal(P<0.05). The mid-puberty (B=-1.10, P<0.01) and late puberty (B=-2.88, P<0.01) had lower social quality of life than the pre-pubertal Significant difference was not found between pubertal dimension and pubertal status(P>0.05). Pubertal KAP impacted on psychological(B=0.02), social(B=0.04), pubertal(B=0.04) dimensions and total quality of life(B=0.09) positively(P<0.01), but no physical dimension(P=0.06). Moderating effect results revealed that pubertal KAP moderated the negative impact of pubertal status on social dimension (B=0.03, P=0.02) and total quality of life(B=0.06, P=0.01), but no psychological dimension(P>0.05). Conclusion Promoting puberty health education of adolescents was the key to improving their quality of life.

Objective: To verify the effectiveness of adolescent peer education on psychological resilience of adolescents, so as to provide a scientific reference for preventing adolescents physical and mental health problems. Methods: The non equivalent comparison group design method was conducted involving 2 towns which were divided into an intervention group(n=732) and a control group(n=881). The intervention group received 1 year peer education. Their resilience and basic information was assessed by using a adolescent psychological resilience scale and a self-designed basic situation questionnaire. Results: After the intervention, in the control group, target concentration, emotional control, family support, interpersonal assistance, and total psychological resilience were reduced by 0.96, 0.72, 0.63, 1.16 and 3.31, respectively(t=5.75, 3.91, 3.52, 5.86, 6.29, P<0.05); in the intervention group, emotional control, interpersonal assistance, and total psychological resilience were increased by 1.05, 0.54 and 1.72, respectively(t=-4.89, -2.46, -2.76, P<0.05). Multiple linear regression showed that the intervention group s target concentration(B=0.38), emotional control (B=0.85), family support(B=0.29), interpersonal assistance(B=0.83), and total psychological resilience(B=2.40) increased higher than the control group(P<0.05). Conclusion Adolescent peer education is effective in improving the target concentration, emotional control, family support, interpersonal assistance, and total psychological resilience.

Objective: To assess the application effect of peer education in mental health education for adolescent primary and middle school students and to provide evidence for promoting the mental health of adolescent primary and middle school students in application. Methods: The non-randomized controlled trial was performed, 4-5 th grade students of two primary and 7-8 th grade students of two middle schools in a district of Chongqing were chosen as peer-education experimental group, and students in the same grade of another two school were chosen as the blank control group. The Mental Health Inventory of Middle School Students scale and self-made questionnaire were used to exam in mental health status of the subjects before and after intervention. Results: The detection rates after intervention of the mental health, compulsion, paranoia, hostility, interpersonal relationship, depression, anxiety, academic stress, emotional imbalance and psychological imbalance (36.8%, 46.1%, 36.6%, 33.3%, 37.2%, 38.8%, 40.9%, 45.7%, 49.2%, 30.3%) in experimental group were lower than those before intervention (39.9%, 55.3%, 38.8%, 37.9%, 43.9%, 40.5%, 42.7%, 48.0%, 52.5%, 32.1%). The detection rate after intervention of maladjustment(39.8%)was higher than that before intervention(37.7%)(P<0.05). Logistic regression analysis showed that the detection rate after intervention of the mental health, compulsion, paranoia, hostility, interpersonal relationship, depression, anxiety and academic stress status of adolescent primary and middle school students in experimental group was 0.63 times more than the rate of the control group(95%CI=0.49-0.81),0.73(95%CI=0.58-0.91),0.68(95%CI=0.54-0.86),0.71(95%CI=0.56-0.91)(P<0.05). Conclusion Peer education is an effective measure and method to improve compulsion,paranoia,hostility,interpersonal relationship,depression,anxiety and intervention effect of adolescent primary and middle school students.

Objective: To explore the relationship between adolescent knowledge-attitude-practice(KAP) and resilience in Chinese left-behind children, and provide the basis to develop the adolescent health education. Methods: A total of 1 244 left-behind children from grade 4-9 was investigated through the self-designed Adolescent KAP Questionnaire and Adolescent Resilience Scale. Results: Male and middle school students had better resilence than female and primary school students in left-behind children(t=4.70，4.27，P<0.01); the left-behind children with harmonious relationship between parents, richer family economic status and democratic parenting style obtained greater resilence(F=35.86，31.66，3.25，57.23，P<0.05), and adolescent KAP had positive prediction on target concentration(B=0.11), emotional control(B=0.07), positive cognition(B=0.09), family support(B=0.05), interpersonal assistance(B=0.09) and total resilience(B=0.41) of left-behind children(P<0.01). Conclusion For left-behind children, adolescent KAP may be have a positive association with resilence and more attention should be paid on adolescent health education.