School bullying is a serious public health concern in many countries worldwide. Over recent decades, several effective anti-bullying prevention programs have been developed. This study aimed to evaluate the effectiveness of an adapted version of the "Equipping Youth to Help One Another (EQUIP) for Educators" (EfE) program in reducing adolescents' engagement in school bullying perpetration by correcting their use of self-serving cognitive distortions (CDs). Furthermore, guided by the vantage sensitivity framework, we investigated whether the intervention effects varied depending on the adolescents' gender and environmental sensitivity. A quasi-experimental pre-test/post-test with a control group design involved 354 Italian middle and high school adolescents (51.7% males; Mage = 14.86, SD = 2.54). Both the control (n = 187) and experimental group (n = 167) completed self-report questionnaires, before and after the intervention. Structural equation modeling revealed a significant moderated mediation effect: highly sensitive males participating in the EfE program decreased their engagement in bullying by reducing CDs, compared to females and those with low- and medium- sensitivity. These findings support the effectiveness of the EfE program in equipping youth to think and act more responsible and shed light on "why" and "for whom" the intervention might work better to counteract school bullying during adolescence.
Keywords: EQUIP for educators; adolescence; bullying perpetration; environmental sensitivity; self-serving cognitive distortions.