Non-suicidal self-injury (NSSI) is a prevalent maladaptive behavior in adolescence, typically distinct from suicidal self-harm and including actions such as cutting, burning, or self-hitting. Adolescence (10–19 years) is a vulnerable developmental stage marked by biological, cognitive, and social change; approximately one in five adolescents experiences a psychiatric disorder, increasing risk for behaviors like NSSI. International estimates indicate NSSI affects a substantial proportion of school-aged youth, with reported point or lifetime prevalence ranges in some settings from about 15–30% in school populations and wider ranges across studies and regions. NSSI is associated with significant psychological consequences, including guilt, shame, persistent negative affect, comorbidity with mood and personality disorders, substance use, and a higher risk of suicide attempts. These factors underscore the need to identify both risk and protective factors that could inform prevention and intervention.
The existing literature is dominated by studies from high-income and Western countries. Research in Iran is limited and fragmented, with few syntheses of factors specifically related to adolescent NSSI and particularly sparse attention to protective factors. Contextual features in Iran—such as family dynamics, parental psychological control, gendered expectations, socioeconomic strain, academic pressure, limited mental-health service access, and sociocultural stigma—may alter the salience and operation of risk and protective factors. The COVID-19 pandemic further altered adolescent well-being internationally and in Iran, where loneliness, resilience, and parental involvement were identified as relevant to adolescent well-being. Given likely underreporting of NSSI and variable prevalence estimates, a focused systematic synthesis of Iranian studies is warranted.
This protocol outlines a systematic literature review to provide a comprehensive overview of Persian- and English-language peer-reviewed studies from 2015 onward that examine risk and protective factors for NSSI and self-harm among Iranian adolescents (ages 10–19). The review aims to summarize associations between identified factors and NSSI, evaluate the robustness of findings across study designs, and organize evidence into clinically meaningful categories such as psychopathology, individual, family, peer, and demographic factors.
Eligible studies include quantitative, qualitative, and mixed-methods designs that investigate NSSI or self-harm among Iranian adolescents aged 10–19 years. Studies must be published in Persian or English from 2015 onward. The protocol distinguishes NSSI (intentional self-injury without suicidal intent) from broader self-harm definitions that include suicidal acts and self-poisoning; both forms of research may be included where relevant to NSSI factors, per the review’s inclusion criteria.
The review will identify studies through searches of international and regional databases: PubMed, PsycINFO, Scopus, Embase, Google Scholar, SID, and Magiran. The protocol indicates a dual-language search (Persian and English) to capture regionally indexed literature. Specific search terms and strings were described in the protocol (details not reproduced here); search coverage begins in 2015 and continues through the most recent available records at the time of review.
Screening and selection of studies will follow PRISMA-P guidelines. Records identified through database searches will be screened against the eligibility criteria; data extraction will proceed from included reports using a standardized extraction form. The protocol states that details of screening, reasons for exclusion at full-text review, and study selection flow will be documented in the final review in line with PRISMA reporting standards.
Data to be extracted include study characteristics (e.g., design, sample age range), measures of NSSI or self-harm, examined risk and protective factors, statistical associations or qualitative findings, and contextual information relevant to interpretation (for example, setting, population characteristics). The standardized extraction form is intended to ensure consistency across reviewers and study types. The protocol notes that no datasets were generated for the protocol itself; extracted data arising from the systematic review will be shared via the Open Science Framework (OSF) upon completion.
Study quality and methodological appraisal will be conducted using the Mixed Methods Appraisal Tool (MMAT), which accommodates assessment across quantitative, qualitative, and mixed-methods studies. The protocol specifies that quality ratings will inform interpretation of the robustness of reported associations between factors and NSSI, but it does not propose excluding studies on the basis of quality alone.
Because studies will include diverse designs and measures, findings will be synthesized narratively. The review will summarize associations between specific risk and protective factors and NSSI, organized into clinically meaningful categories such as psychopathology, individual characteristics, family processes, peer influences, and demographic factors. The narrative synthesis will describe direction and consistency of associations, note the strength and limitations of the evidence base, and highlight gaps, particularly in research on protective factors in the Iranian context.
The protocol emphasizes that proximal psychological vulnerabilities (e.g., difficulties in emotion regulation, psychiatric disorders) may be similar across cultures but that sociocultural antecedents and the relative importance of factors may differ in Iran. Reported Iranian correlates of increased NSSI risk in prior studies include older adolescent age, cigarette smoking, team sport membership, physical fighting, general risk-taking behaviors, lower self-esteem, weak family psychological functioning, and low perceived social support. Socioeconomic strain, academic pressures, and stigma around mental health are noted as additional contextual drivers. The authors highlight the need for culturally and locally appropriate interpretation of findings and for improved representation of low- and middle-income, non-Western populations in the evidence base.
The protocol reports no external funding and declares no competing interests. Ethics approval is not applicable to the protocol stage; the authors plan to make extracted study data and synthesis outputs publicly available via OSF when the review is complete. The protocol itself is registered with PROSPERO (CRD420261286909) and published in PLOS One (received April 2, 2026; accepted September 14, 2026; published September 28, 2026). The final review will present a PRISMA flow diagram and narrative synthesis, and will discuss implications for prevention, assessment, and intervention targeted at Iranian adolescents.