Abstract Introduction: Nonsuicidal self-injury (NSSI), often known as self-harm behavior may begin at age 11 and peak between the ages of 14 and 16. Adolescents who have difficulties in communicating and expressing their feelings and emotions may develop conduct disorder and NSSI. The roles of teachers in the classroom can be a very important protective factor. There are limited studies in Indonesia regarding NSSI despite increased awareness of its effects on adolescents’ well-being. This study aimed to raise awareness among students and teachers about self-harm and to reduce self-harming behaviors among adolescents. Materials and Methods: This cross-sectional study involved 232 students from Petra Christian School in Malang, Indonesia. Participants were divided into groups regarding their age (12–15 years: 134 students, 57.3%; 16–17 years: 83 students, 35.5%; 18–20 years: 17 students, 7.3%), sex (male: 99 students, 42.3%; female: 135 students, 57.7%), and educational level (junior high: 84 students, 35,9%; senior high: 150 students, 64,1%). We analyzed self-harm tendency using a knowledge score instrument, Inventory of Statements About Self-Injury, Strengths and Difficulties Questionnaire (SDQ), Pediatric Symptom Checklist (PSC), and Patient Health Questionnaire-9 (PHQ-9) pre- and postintervention. We used a knowledge score instrument to measure teachers’ knowledge before and after intervention regarding self-harm behavior or NSSI. Results: A multivariate analysis identified key predictors of self-harm ( R ² =0.132), with the strongest positive associations being previous professional help (β =81.178), prior self-harm (β =35.484), PHQ-9 (β =3.914), and PSC scores (β =2.388). Male sex (β = −38.483), Intelligence Quotient (β = −0.324), emotional quotient (β = −0.894), and SDQ (β = −1.282) were inversely related to self-harm. Postintervention analysis revealed significant improvements in knowledge ( P < 0.001) and SDQ scores, indicating better emotional and behavioral well-being. However, changes in PSC ( P = 0.101) and PHQ-9 ( P = 0.177) were not statistically significant. Teachers also showed significant knowledge gains ( P < 0.001) following the intervention. Conclusion: Providing knowledge modules about self-harm is vital for students to reduce the tendency to engage in self-harm. Teaching knowledge to teachers about NSSI in students is also an essential step in detecting students with tendencies towards self-harm behavior.
Putri et al. (Fri,) studied this question.