Background: Repetitive nonsuicidal self-injury (R-NSSI) is a serious public health issue prevalent in adolescence. However, the key factors and mechanisms driving the repetition and addiction of self-injurious behavior remain unclear. This study aims to understand R-NSSI by examining the significant developmental characteristics of adolescence, specifically focusing on the imbalance between emotional reactivity and cognitive control through longitudinal and ERP evidence.
Methods: In Study 1, data from 2,998 adolescents (aged 10-16 years, 57% male) were collected over two survey waves. Polynomial regression and response surface analysis estimated the imbalance between emotional reactivity and cognitive control among R-NSSI. In Study 2, 55 adolescents (aged 12-15 years, 45.6% male) with R-NSSI and without NSSI completed a two-choice emotional oddball task while ERP data were recorded. A follow-up survey on NSSI was conducted
Results: In Study 1, The prevalence of R-NSSI was 2.37%, with 371 adolescents meeting the criteria (NSSI scores ≥5; 55.3% female; mean age 13.05 ± 0.87 years). Among adolescents with R-NSSI, greater discrepancies between emotional reactivity and cognitive control predicted higher NSSI frequency (95% CI: 0.004-0.30) and stronger addictive features (95% CI: 0.04-0.27) nine months later. In Study 2, adolescents with R-NSSI exhibited blunted P3d responses to both negative and positive emotions compared to those without NSSI, indicating greater discrepancies between emotional reactivity and cognitive control. Additionally, baseline P3d was negatively correlated with R-NSSI outcomes six months later.
Conclusions: The findings suggest that an imbalance between emotional reactivity and cognitive control play an important role in the progression of R-NSSI. Adolescents with R-NSSI demonstrate deficits in controlling emotional reactivity, suggesting that P3d may be a psychophysiological marker of risk for R-NSSI. Thus, therapeutic targeting of emotional inhibition may help to reduce R-NSSI during adolescence.