According to research findings, self-harm occurs more in adolescence than in other developmental periods. In addition to affecting social and academic functions, this disorder can lead to serious life risks. This study was conducted to investigate the relationship between insecure attachment styles and self-harm with the mediation of resilience and mentalization. The method of this study was correlation. The statistical population included all first and second-high school students of one education district of Zahedan in the academic year of 2022-2023. Using a multi-stage cluster sampling method, 305 students who scored five or higher on the Self-harm questionnaire were selected. To collect data, the Revised Adult Attachment Scale, the Resilience Questionnaire, and the Mentalization Questionnaire were used. The data were analyzed using structural equations modeling using AMOS and SPSS software. The evaluation of the model showed an acceptable fit with the obtained data. Insecure attachment styles had significant effects on self-harm in adolescents with the mediation of resilience and mentalization (P < 0.05). Moreover, resilience and mentalization had direct effects on self-harm (P < 0.05). The research results indicated that insecure attachment styles could be a strong predictor of self-harm in adolescence due to resilience and mentalization. Considering the significant relationship between the research variables and this disorder, it is suggested that officials prevent the intergenerational transmission of insecure attachment style and self-harm by holding educational workshops for parents.IntroductionSelf-harm can be defined as an action in which an individual intentionally harms himself through cutting, scratching, hitting, or burning his skin with or without suicidal thoughts (Peh et al., 2017). Self-harm, which generally begins in adolescence, is associated with low mental health, unstable relationships, and possible suicide (Asranow et al, 2011).Research has shown that insecure attachment is associated with self-harm. People with insecure attachment have less resilience. In other words, such people are less able to adapt when facing adversity, trauma, and stress (Craparo et al., 2018). People with low resilience may show self-injurious behaviors when facing stressful factors, instead of solving and managing problems (Ran et al., 2020).Another important variable related to self-injury is mentalization. Mentalization refers to the ability to pay attention to mental states such as oneself and others’ feelings and desires. Low mentalization capacity is associated with insecure attachment and self-harm. Given the consequences of self-harm, it is important to identify the underlying factors to understand this disorder better. Therefore, this study was conducted to investigate the structural relationship between insecure attachment styles and self-harm with the mediation of resilience and mentalization. MethodThe study is a correlational one. The data were analyzed through structural equation modeling. The research population included all first and second-high school students of one education district in Zahedan in the academic year of 2022-2023. After coordination with the Ministry of Education, 12 schools and five classes from each school were randomly selected from 54 schools through a multi-stage cluster sampling method. The target sample was calculated based on Kline’s opinion (Kline, 2011). Klein considered the number of samples based on the sample size ratio to the parameter, which was considered at least 10 to 1 in structural equations. Klein claimed that a minimum size of 200 people could be supported. Using the multi-stage cluster sampling method, 305 students who scored five or higher on the Self-harm Questionnaire (Sanson and Sanson, 1998) were selected. To collect data, the Revised Adult Attachment Scale (Collins and Reed, 1990), Resilience Questionnaire (Connor and Davidson, 2003), and Mentalization Questionnaire (Dimitrovich, 2017) were used. Data were analyzed using AMOS (version 23) and SPSS (version 23) software. FindingsAll fit indices (i.e., AGFI, NFI, CFI, GFI, and RMSEA) were at the desired level. This showed that the hypothesized model had an acceptable fit with the research data. The results of this research study showed that ambivalent and avoidant insecure attachment styles had significant indirect effects on self-harm with the mediation of resilience. Resilience had a significant negative relationship with self-harm. In addition, insecure ambivalent, and avoidant styles with the mediation of mentalization could be considered a strong predictor of self-harm. Furthermore, mentalization had a significant negative relationship with self-harm. DiscussionThe present study was conducted to investigate the roles of insecure attachment styles in self-harm with the mediation of resilience and mentalization. First of all, the findings supported the indirect relationship between insecure attachment styles and self-harm with the mediation of resilience as well as the direct relationship between resilience and self-harm. In this regard, Balbi (1988) stated that an important part of how resilient a child is against the pressures of life depends on his attachment style (Svanberg, 1998). Insecure attachment styles reduce an individual’s resilience against difficult life events, and this may cause the individual to turn to self-harm when facing severe stress and anxiety. Moreover, the findings of the current study showed the existence of an indirect relationship between attachment styles and self-harm with the mediation of mentalization as well as the existence of a direct relationship between mentalization and self-harm. People with insecure attachment have difficulty acquiring mentalizing capacity and the lack of this capacity leads them to express their painful emotions in an inappropriate way such as self-harm during emotional arousal (Stagaki et al., 2022).Regarding the limitations of this study, it was limited to one city and one age group. Thus, generalization of the results should be done with caution. In addition, using structured, semi-structured, or unstructured interviews and qualitative research methods, more trustable findings could be obtained.