Locus of Control, Self-Efficacy, and Emotion Regulation as Personality-Based Predictors of Non-Suicidal Self-Injury

Non-Suicidal Self-Injury (NSSI) is a significant concern among adolescents and presents an important challenge in school settings. This quantitative predictive-correlational study examined whether locus of control, self-efficacy, and emotion regulation predicted NSSI among 117 purposively selected Senior High School (SHS) students of Muntinlupa National High School during School Year 2025–2026. Data were collected using four standardized instruments: the Multidimensional Locus of Control Scale (MLCS), General Self-Efficacy Scale (GSE), Emotion Regulation Questionnaire (ERQ), and Deliberate Self-Harm Inventory (DSHI). Descriptive statistics, including mean and standard deviation, and multiple linear regression were employed to analyze the data. The findings indicated moderate levels of locus of control, self-efficacy, and emotion regulation, particularly cognitive reappraisal and expressive suppression. NSSI was rarely engaged in, with an overall mean of 1.80 (SD = 0.21). Multiple regression analysis revealed that emotion regulation was the only significant predictor of NSSI (β = −0.237, p = .021), whereas locus of control and self-efficacy did not significantly predict NSSI. The negative regression coefficient indicates that a one-standard-deviation increase in emotion regulation was associated with a 0.237-standard-deviation decrease in NSSI, holding the other predictors constant. These findings highlight the importance of strengthening students' emotion-regulation capacities as part of school-based efforts to address and prevent NSSI. The study further underscores the need for a deeper understanding of the psychological factors associated with NSSI to inform appropriate preventive and supportive interventions in school settings.