Objective: To develop the Adolescent Peer Bullying Knowledge-Attitude-Practice (KAP) Questionnaire and to evaluate its reliability and validity, so as to provide an effective tool for evaluating the KAP level regarding peer bullying among adolescents. Methods: A preliminary framework was developed through literature review, expert consultation, and group discussions. In September 2024, 2 203 students in grades 7 to 9 from two regular junior high schools in Anhui Province were selected using cluster sampling for a preliminary survey aimed at questionnaire development, including item screening and reliability and validity testing. Results: The initial KAP questionnaire on adolescent peer bullying consisted of 25 items: two items, "Behavior 6" and "Behavior 7", were excluded as their correlation coefficients with the total KAP score being only 0.08 and 0.05, respectively, falling below the preset criteria(0.4). The final questionnaire comprised 23 items, divided into three dimensions: knowledge, attitude, and behavior. Reliability testing showed that the overall Cronbach α coefficient of the questionnaire was 0.89, with Cronbach α coefficients for the knowledge, attitude, and behavior dimensions being 0.91, 0.67 and 0.79, respectively. The overall splithalf reliability of the questionnaire was 0.87, with split half reliabilities for the knowledge, attitude, and behavior dimensions being 0.82, 0.64 , and 0.66, respectively. Testretest reliability ranged from 0.82 to 0.97. Confirmatory factor analysis results indicated that the questionnaire had RMSEA=0.062, NFI=0.924, CFI =0.931, with good discriminant validity. Conclusion The developed KAP questionnaire on adolescent peer bullying demonstrates good reliability and validity and can be used as an assessment tool for evaluating the KAP level regarding peer bullying among adolescents.

Objective: To evaluate the effectiveness of a family-school-community integrated intervention based on the microsystem theory in reducing peer bullying among junior high school students, so as to provide empirical evidence and feasible pathways for junior high school students bullying prevention and control in China. Methods: A combining convenience with clustering method was employed to select 6 268 students from three regular junior high schools in Fuyang and Anqing cities, Anhui Province, as the study subjects in October 2024, and randomly assigned by drawing lots to three groups: family-school-community integrated intervention ( n =2 063), school only intervention ( n =1 864), and control group ( n =2 341). From October 10, 2024, to January 10, 2025, the intervention was implemented for three months using posters, brochures, and videos, with one session every half month, each lasting 40 minutes. The family-school-community integrated intervention group received multi level interventions involving families, schools, and communities, while the school only intervention group received only school based interventions. The control group received routine school health education but no other interventions. Before and after the intervention, data on peer bullying among junior high school students were collected using the Peer Bullying Scale, and comparison of detection rate of peer bullying by Chi square test. Results: After the intervention,group comparison results showed that the incidence rates of various types of peer bullying in the family-school-community integrated intervention group, the school only intervention group, and the control group all showed statistically significant differences ( χ 2=28.61-66.85, all P <0.05). The detection rates of verbal bullying ( 7.51 %), relational bullying (5.62%), physical bullying (3.34%), cyberbullying (1.75%), being bullied (10.81%), verbal bullying others (2.67%), relational bullying others (1.55%), physical bullying others (1.36%), cyberbullying others (1.41%), and overall peer bullying (3.64%) in the family-school-community integrated intervention group were all lower than those in the control group (12.52%, 11.58%, 6.24%, 5.00%, 19.14%, 7.56%, 4.49%, 4.53%, 3.80%, 9.40%); additionally, the detection rates of verbal bullying others, overall peer bullying , verbal bullying, and being bullied , in the family-school-community integrated intervention group were all lower than those in the school only intervention group (4.67%, 6.65%, 13.14%, 16.42%), with statistically significant differences ( χ 2=30.04, 48.49, 19.75, 34.60, 58.89, 52.65, 31.32, 37.37, 24.14, 58.26; 11.25, 18.53, 33.93, 26.41, all P <0.016 7). Group comparison showed that in both intervention groups, the majority of peer bullying behaviors decreased after the intervention ( χ 2=4.86-171.01, all P <0.05). Conclusions The family-school-community integrated intervention based on the microsystem can effectively reduce peer bullying among junior high school students, with better efficacy than the single school intervention. The model can serve as a practical reference for establishing a multi level prevention and intervention system for junior high school students bullying in China.