Co-occurrence patterns of adverse childhood experiences and their associations with non-suicidal self-injury and suicidal behaviors and gender difference among middle school students: A three-city survey in China

Previous research has found increasing evidence of adverse childhood experiences (ACEs) leading to non-suicidal self-injury (NSSI) and suicidal behaviors. Most studies have focused on a certain type or timing of ACEs or the patterns of multiple types; however, few of them have examined the patterns of ACEs combined types and timing and the gender differences in the association between ACEs and self-harming behaviors.A cross-sectional survey was conducted in three Chinese cities from November 2020 to May 2021. We asked 16,853 middle school students to anonymously complete a questionnaire to provide the details of their own ACEs and NSSI or suicidal behaviors.Latent class analysis identified four classes: high ACEs (10 %), high abuse/neglect (20.3 %), moderate ACEs (26.7 %) and low ACEs (43 %). Logistic regression models demonstrated that students in the high ACEs, high abuse/neglect and moderate ACEs subgroups were more likely to engage in NSSI and suicidal behaviors than students with low ACEs. Compared with boys, girls had a higher probability of engaging in NSSI and suicidal behaviors when exposed to the same level of ACEs.Co-occurrence of ACEs is associated with high risk of NSSI and suicidal behaviors. Our findings recognized the most dangerous patterns and latent class membership, which supply the evidence for policy makers to adopt preventive measures to protect high-risk individuals. Strategies to relieve the impact of ACEs, especially on girls, need to be considered comprehensively.The study was limited by cross-sectional design, as causality could not be confirmed. In addition, because our survey was retrospective, potential recall bias can not be ignored.