Objective: To explore the combined effect of health literacy and nonsuicidal selfinjury on suiciderelated behaviors in junior middle school students, so as to provide reference for suicide prevention. Methods: During May to June 2023, a selffilling questionnaire survey was conducted among 7 367 junior middle school students selected by the methods of multistage stratified cluster sampling combined with conventient sampling in Chongqing. And a binary Logistic regression model was established to analyze the association of health literacy and NSSI with suiciderelated behaviors. Results: The detection rates of suicidal ideation, suicide planning, and suicide attempt among junior middle school students were 27.99%, 9.84%, and 4.64%, and the detection rate of NSSI was 38.03%, the rates of possessing total health literacy, functional health literacy, interactive health literacy, and critical health literacy were 62.68%, 66.51%, 54.24%, and 72.65%, respectively. Binary Logistic regression analyses showed that the absence of total health literacy and the three dimensions of health literacy and NSSI were positively correlated with suicidal ideation, suicide planning, and suicide attempt in junior middle school students (OR=1.42-10.30), and there were combined effects (OR=7.43-18.71) (P<0.05). Conclusions Lack of health literacy or the presence of NSSI and their coexistence increase the risk of suiciderelated behaviors, and health literacy level should be improved in junior middle school students to reduce NSSI and thereby prevent suiciderelated behaviors.

Objective: To explore the association between adverse childhood experiences (ACEs) and nonsuicidal selfinjury (NSSI) and suiciderelated behaviors among junior high school students, so as to provide a reference basis for the prevention of junior high school students suicide. Methods: From May to June 2023, a total of 7 392 junior high school students in three districts and counties of Chongqing were selected for self-administered questionnaire survey by stratified cluster sampling and convenience sampling methods. The questionnaire survey was conducted using the Chinese version of the Childhood Trauma Scale, Adolescent NSSI Assessment Questionnaire, and Suicide Related Behavior Questionnaire. Statistical analysis was performed by using χ 2 test, multifactorial Logistic regression model, and additional interaction analysis was used to calculate the estimated relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy index (S), as well as 95% CI . Results: The detection rate of NSSI among junior high school students was 38.03%, the detection rate of ACEs was 41.76%, and the detection rates of suicidal ideation, suicide planning, and suicide attempt were 27.99%, 9.90%, and 4.75%, respectively. ACEs and its dimensions, and NSSI were the influencing factors for suiciderelated behaviors (OR=1.83-10.66, P<0.01). The result of the additive interaction showed that ACEs and NSSI, PN and NSSI, EA and NSSI, EN and NSSI all had additive interactions on suiciderelated behaviors (RERI=0.45-39.15, AP=0.10-1.09, S=1.02-3.92). And ACEs and its dimensions had additive interactions with NSSI on suiciderelated behaviors, for junior high school students with both ACEs and NSSI had 11.45, 20.38, and 28.76 times the risk of suicidal ideation, suicidal planning, and suicidal attempts as compared to junior high school students without ACEs and without NSSI (P<0.05). Conclusions ACEs and NSSI among junior high school students have an additive interaction effect on suicide related behaviors. ACEs and NSSI should be reduced to prevent suicidal behavior among middle school students.