Psychosocial factors associated with non-suicidal self-injury in Iranian adolescents and young adults: a scoping review protocol

Abstract

Introduction

Non-suicidal self-injury (NSSI) is defined as the deliberate harm to one’s body without suicidal intent. Although individuals engaging in NSSI do not intend to die, repetitive self-injury may increase the risk of future suicidal behaviour through reduced fear of death and increased pain tolerance. Global lifetime prevalence estimates of NSSI range from 4.2% in adults to 15.4% in adolescents, with an observed increase during the COVID-19 pandemic. In Iran, the reported prevalence of NSSI among adolescents and young adults is approximately 22%; however, comprehensive and culturally contextualised evidence remains limited. Psychosocial, interpersonal and ecological factors contribute to NSSI, yet no prior study has systematically mapped these determinants within an integrated, multilevel framework in the Iranian context.

Objective

This scoping review aims to identify and map intrapersonal, interpersonal and ecological psychosocial factors associated with NSSI among Iranian adolescents and young adults, summarising quantitative and qualitative evidence and highlighting gaps for future research and intervention planning.

Methods and analysis

Following Arksey and O’Malley’s six-stage framework, with enhancements from the Joanna Briggs Institute guidelines, a comprehensive search was conducted across international (PubMed, Scopus, Web of Science, PsycINFO, Embase) and national (SID, Magiran, Noormags) databases. Two reviewers will independently conduct screening, data extraction and thematic coding. A third reviewer will resolve any discrepancies. Findings will be synthesised using a directed narrative synthesis combined with integrative thematic analysis. Psychosocial factors will be mapped to an integrated framework combining Nock’s functional model and Bronfenbrenner’s ecological systems theory. Methodological quality will be appraised using the Mixed Methods Appraisal Tool.

Ethics and dissemination

This scoping review will be conducted based on published and publicly available literature; therefore, no individual informed consent is required. Ethical approval has been obtained from the Ethics Committee of Ferdowsi University of Mashhad (Approval code: IR.UM.REC.1404.282). The findings will be disseminated through publication in a peer-reviewed journal, conference presentations and academic workshops to inform researchers, clinicians and policymakers about the factors associated with NSSI among Iranian adolescents and young adults.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• Adherence to Preferred Reporting Items for Systematic Review and Meta-Analysis extension for Scoping Reviews and Joanna Briggs Institute guidance ensures transparent and methodologically rigorous conduct and reporting.

• The inclusion of Persian-language and English-language studies with no restrictions on publication year enhances the comprehensiveness of the search strategy and increases the likelihood of identifying all relevant evidence.

• Independent dual screening and data extraction minimise selection and extraction bias.

• Heterogeneity in study designs and measurement instruments across included studies may limit comparability.

• The scoping review design, together with the anticipated scarcity of high-quality qualitative and longitudinal studies, precludes causal inference and may limit generalisability beyond the Iranian sociocultural context.

Introduction

Non-suicidal self-injury (NSSI) is defined as the deliberate, damage to one’s body without suicidal intent.^{1 2} Menninger earlier described self-harm as a ‘self-destructive’ act and a ‘gesture against suicide’, suggesting it serves as a strategy to avoid death.³ Although individuals engaging in NSSI do not intend to die, repeated self-injury may increase the risk of future suicidal behaviour⁴ by reducing fear of death^{5 6} and increasing pain tolerance.⁷ The Diagnostic and Statistical Manual of Mental Disorders-5-TR⁸ recognises NSSI as a distinct diagnostic entity.

Global lifetime prevalence estimates of NSSI are 4.2% in adults, 10.5% in young adults and 15.4% in adolescents.⁹ Adolescents are the most vulnerable group, with prevalence rising from 17% before the COVID-19 pandemic to 27% during the pandemic.¹⁰ In Iran, the prevalence of NSSI among adolescents and young adults is approximately 22%,¹¹ although up-to-date national data are not available.

Several theoretical models have been proposed to explain NSSI. Emotion regulation and experiential avoidance models emphasise negative reinforcement, whereas functional models also highlight positive reinforcement, such as relief from distress or increased positive affect, in the repetition of the behaviour. Cognitive–emotional¹² and benefits-and-barriers¹³ models explain the initiation of NSSI by considering self-efficacy beliefs and perceived initial obstacles. Empirical evidence indicates that emotion regulation plays a central role across all models.¹⁴

Risk factors for NSSI are observed at intrapersonal, interpersonal and structural levels. At the intrapersonal level, vulnerabilities include negative affect toward self-criticism, perfectionism, anger, emotion dysregulation and experiences of childhood trauma.15,19 At the social and cultural level, the roles of cultural norms, socio-economic status, discrimination, social exclusion, educational systems and peer networks have been emphasised.20,22 Meanwhile, structural factors such as gender-based violence disproportionately affect women.²³ Iranian studies similarly highlight impulsivity and executive dysfunction,²⁴ negative self-concept and trauma,²⁵ and engagement in risky behaviours.²⁶ We will categorise identified factors according to an adapted ecological model (intrapersonal, interpersonal and ecological/structural levels) to guide the synthesis and presentation of results.

Despite extensive research, interventions for NSSI show limited effectiveness. Systematic reviews suggest that the most effective treatments are those designed based on a deep understanding of the psychological and social risk factors underlying NSSI,^{27 28} and that individuals’ cultural and bioecological contexts play a key role in the manifestation of this behaviour.²³ Previous reviews in Iran have focused only on some individual or social factors,²⁹ and no study in the past 50 years has provided an integrated, multilevel framework.

This scoping review protocol aims to synthesise existing evidence, identify research gaps and provide a theoretical foundation for culturally informed preventive and therapeutic interventions for NSSI among adolescents and young adults in Iran.

Objectives

The primary objective of this scoping review is to identify and map the psychosocial factors—including individual, familial and social determinants—associated with NSSI among Iranian adolescents and young adults. The secondary objectives are to:

1. Summarise the most commonly studied psychological and social factors reported in the literature.

2. Examine reported differences in NSSI patterns based on sex and age groups.

3. Assess the methodological quality of existing studies.

4. Provide evidence-based recommendations to guide future research and the development of preventive interventions.

Methods

Given the conceptual breadth and heterogeneity of studies on the factors associated with NSSI among Iranian adolescents and young adults, and since the aim is to identify and map the scope and characteristics of existing evidence rather than systematically synthesise and compare results,³⁰ a scoping review methodology was chosen. This approach enables a comprehensive examination of diverse study types and the identification of knowledge gaps, and it provides a foundation for conducting a systematic review in a subsequent phase.³¹

The current scoping review will be conducted following the six-stage framework of Arksey and O’Malley,³⁰ with consideration of the supplementary recommendations by Levac et al (2010)³² and the Joanna Briggs Institute (JBI) guidance.³³ The main stages of this framework include: (1) defining the research question, (2) identifying relevant studies, (3) selecting eligible studies, (4) charting (extracting) the data, (5) collating, summarising and reporting the results, and (6) (optional) stakeholder consultation.

To define the study scope, develop inclusion and exclusion criteria and design the search strategy, the Population–Concept–Context (PCC) framework was used. Table 1 (below) presents the PCC framework. Keywords and search combinations were developed based on the PCC components, and the exact search strings are provided in online supplemental file 1.

Table 1. Research questions framework.

Component	Description
Population	Adolescents (12–18) and young adults (18–24)
Concept	Psychosocial factors associated with NSSI
Context	Iran

Note: this table summarises the Population, Concept and Context components applied in framing the research question for this scoping review.

NSSI, non-suicidal self-injury.

Stage 1: identifying the research question

The research question was defined using the PCC framework and is summarised in box 1.

Box 1. Search strategy in Scopus database.

Query search in Scopus

TITLE-ABS-KEY(“self-harm” OR “self harm” OR self-injur* OR “non-suicidal self-injury” OR NSSI OR “self-injury” OR “deliberate self-harm” OR “self-inflicted injury” OR self-cut* OR self-burning OR self-poison* OR self-mutilat* OR self-destruct* OR parasuicide OR “self abuse”) AND TITLE-ABS-KEY(adolescen* OR teen* OR youth OR “young people” OR “young adult*” OR “high school student*” OR “university student*”) AND TITLE-ABS-KEY(Iran OR Iranian)

Primary question

Which psychosocial factors (individual, familial, social) are associated with NSSI among Iranian adolescents and young adults?

Secondary questions

1. What are the most common psychological factors reported in this population?

2. Are there meaningful differences in NSSI patterns between sexes (female vs male) and between age groups (adolescents vs young adults)?

3. What are the most commonly reported social factors in this population?

4. What are the methodological strengths and limitations of the existing studies in this field?

Stage 2: identifying relevant studies

The search strategy was designed and executed in accordance with the JBI three-step approach.³³

Step 1: An initial limited search was conducted in PubMed and Scopus to identify relevant text words from titles and abstracts, as well as controlled vocabulary/index terms (Medical Subject Headings/Emtree) related to NSSI and psychosocial factors. Based on this preliminary search, and following review by two adolescent mental health specialists and the supervisory team, the final set of search terms was refined using the PCC framework.

Step 2: Comprehensive searches will subsequently run in international databases (PubMed, Scopus, Web of Science, PsycINFO and Embase) and Iranian national databases (SID, Magiran, Noormags). Searches were completed on 15 October 2025. All retrieved records were exported and imported for screening without restrictions on study design. Boolean operators (AND/OR) and truncation (*) were applied as appropriate to maximise sensitivity and ensure reproducibility. In designing the search, we made a conceptual distinction between NSSI and suicidal behaviours; studies examining both were eligible only if NSSI-specific results were reported separately or could be extracted independently.

Step 3: To enhance completeness and identify evidence not consistently indexed in bibliographic databases, supplementary searching was undertaken with no date restrictions, consistent with the main inclusion criteria. This included searching the same international (Scopus, Web of Science, PubMed) and national (SID, Magiran, Noormags) databases for conference proceedings using document-type filters; searching IranDoc for Persian-language theses and dissertations; manually searching the websites of the Iranian Ministry of Health and Medical Education and the National Organisation for Youth for relevant reports; conducting a comprehensive search in Google Scholar using the same search terms with no restrictions on the number of records screened; backward citation tracking of reference lists from included studies and relevant reviews; and consulting experts in adolescent mental health and NSSI in Iran to identify ongoing or unpublished studies. All documents identified through these methods were subject to the same eligibility screening as database records and will be documented in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram.

An example of the Scopus search strategy is provided in box 1, and full search strategies for all sources are presented in online supplemental file 1.

Stage 3: study selection

The study selection process will be conducted in accordance with the PRISMA extension for Scoping Reviews (PRISMA-ScR) guidelines³⁰ and the JBI guidance for evidence synthesis.³⁰ All records retrieved from the databases will be imported into EndNote; duplicates will be removed automatically and then checked manually.

Selection will occur in two stages. In the first stage, two reviewers will independently screen titles and abstracts of all identified records against prespecified eligibility criteria. Studies will be retained if they focus on NSSI among Iranian adolescents (aged 12–18 years) or young adults (aged 18–24 years) and examine psychosocial factors. In the second stage, the same two reviewers, using the same eligibility framework, will assess full texts of potentially eligible studies independently. A summary of the inclusion and exclusion criteria is presented in table 2. A pilot of 50 records will be conducted; Cohen’s kappa will be calculated and κ≥0.70 will be considered acceptable. Any disagreements between reviewers will be resolved through discussion and, if necessary, by consulting a third reviewer or subject-matter experts. In addition to database searches, supplementary studies will be identified through manual searching and a snowballing approach (screening reference lists of included studies). The entire study selection process will be documented using a PRISMA flow diagram, showing the numbers of records identified, screened, excluded and included at each stage. This systematic and transparent approach is designed to minimise selection bias and to enhance the rigour and reproducibility of the review.

Table 2. Inclusion and exclusion criteria.

Criterion	Description
Population	Studies will be included if the authors report that at least 80% of participants are aged between 12–24.
Concept/definition	NSSI as defined by Nock2: intentional, self-directed behaviours that cause damage to bodily tissue, performed without suicidal intent.
Phenomenon of Interest	Psychosocial factors (eg, emotional, cognitive, social or environmental correlates) associated with NSSI.
Publication date	No date restrictions (database inception to the final search date).
Language	Articles published in Persian or English.
Study designs	Quantitative (eg, cohort, cross-sectional, case–control), qualitative (eg, phenomenology, grounded theory) and mixed-methods studies.
Exclusion criterion
Studies for which the full text is not accessible. Review articles, meta-analyses, commentaries or editorial publications. Studies focusing solely on suicidal behaviour without explicit reference to or measurement of NSSI. Studies where less than 80% of the sample falls within the specified age range of 12–24 years.

NSSI, non-suicidal self-injury.

Stage 4: data charting

Data charting will be conducted using a standardised extraction form,^{31 33} developed in alignment with the JBI guidance for evidence synthesis and the PRISMA-ScR checklist. The form will be pilot-tested on a small sample of included studies (5–10 studies) to ensure clarity, consistency and comprehensiveness and will be iteratively refined as needed throughout the review process. Two reviewers will independently extract data from all included studies, with any disagreements resolved through discussion or consultation with a third reviewer.

The data charting form will capture both bibliographic information and detailed content from each study. The domains to be extracted are summarised in table 3. To ensure transparency and reproducibility, the charting process will remain iterative, and the extraction form will be updated if new concepts emerge during analysis. All changes will be recorded and documented. Extracted data will be managed using Microsoft Excel for tabulation, and qualitative findings will, if necessary, be imported into qualitative analysis software to facilitate thematic synthesis. This structured and systematic approach ensures that all relevant data are comprehensively extracted and consistently analysed across included studies. The preliminary data charting form is available in online supplemental file 2.

Table 3. Data extraction domains.

Domain	Description/example
Bibliographic information	Author(s), year, journal, country
Study characteristics	Objectives, study design, methodology (quantitative/qualitative/mixed-methods)
Population	Age, sex, sample size, recruitment setting
Context	Socio-cultural and geographical conditions, urban/rural
Concept/factors	Psychosocial, cultural, individual or other factors; protective or risk factors
NSSI characteristics	Definition, distinction from suicidal behaviour, prevalence, methods
Key qualitative findings	Themes and patterns related to causes or influencing factors
Key quantitative findings	Prevalence, correlations, regression results
Author notes	Conclusions, limitations, recommendations

NSSI, non-suicidal self-injury.

Stage 5: data synthesis

Data synthesis will be conducted using a directed narrative synthesis combined with integrative thematic analysis adequately to reflect both quantitative and qualitative evidence.³³

Synthesis Procedure

1. Development of summary tables:

   • A table will present the characteristics and methodological quality of the included studies.

   • Intrapersonal factors associated with NSSI, stratified by adolescents and young adults, will be compiled in a table with relevant statistical indicators.

   • A separate table will similarly present interpersonal and ecological factors.

2. Thematic synthesis:

   • A thematic analysis will be conducted to identify dominant themes, sub-themes and themes with limited supporting evidence, which will be presented in a dedicated table.

3. Comparative analysis:

   • All identified themes and factors will be analysed and compared in parallel for the ‘adolescent’ (12–18) and ‘young adult’ (18–24) subgroups to delineate shared and distinct psychosocial pathways.

4. Theoretical integration:

   • To comprehensively examine the interaction of multilevel factors that contributed to NSSI, we will adopt Bronfenbrenner’s ecological systems framework as an organising heuristic to classify and map risk and protective factors for NSSI across nested levels of influence (individual, interpersonal, institutional and societal).³⁴ To capture proximate mechanisms of self-injury, we integrate this multilevel framing with Nock’s functional model, which characterises NSSI in terms of intrapersonal and interpersonal functions.² The combined approach enables identification of which functional processes operate at the individual level and which contextual features at higher ecological levels may precipitate, reinforce or buffer those processes. Importantly—consistent with recent reflections on applications of ecological theory in mental-health research—we use the ecological framework as a conceptual and classificatory tool for organising empirical evidence and designing multilevel interventions, not as a claim of causal proof; establishing causal links would require longitudinal and experimental designs beyond the scope of this protocol.³⁵ A conceptual illustration of how the ecological levels and functional mechanisms may be combined is shown in table 4.

5. Assessment of evidence robustness: The robustness of evidence for identified themes will be evaluated and stratified based on a multidimensional assessment of the volume of evidence, methodological quality of contributing studies and the consistency of reported findings. This will result in classifications such as strong evidence, moderate evidence and weak evidence. Although critical appraisal is not mandatory in scoping reviews, we will appraise methodological quality to contextualise confidence in the mapped evidence, not to exclude studies. Two reviewers will independently apply the Mixed Methods Appraisal Tool (MMAT)³⁶; discussion or a third reviewer will resolve disagreements. MMAT findings will be reported descriptively and will inform the evidence robustness classification for each factor/theme.

Table 4. Integrated intrapersonal/interpersonal and ecological model of NSSI.

Ecological level	Intrapersonal factors	Interpersonal factors	Examples/notes
Microsystem	Emotion regulation difficulties Shame, self-criticism	Family conflict Peer rejection Harsh parenting	Immediate social environment influencing daily stress and coping
Mesosystem/exosystem	Internalisation of social expectations Self-esteem fluctuations	Interactions among family, school, peers Community support or online influence	Bridges between microsystems and wider community factors
Macro system/chronosystem	Cultural values and identity conflict Coping with societal pressure	Cultural norms, policy, educational expectations	Broader societal and temporal influences
Note	Bidirectional influences exist between all levels	Intrapersonal and interpersonal mechanisms affect each other	Model suitable for scoping review protocol illustration

Note: this model is a given two-dimensional matrix for the scoping review study. It integrates intrapersonal vulnerabilities and interpersonal dynamics with ecological systems theory35 (Bronfenbrenner, 1979). Each cell highlights how specific psychological processes interact with contextual layers to contribute to NSSI.

NSSI, non-suicidal self-injury.

In this scoping review, the integration of quantitative and qualitative evidence will proceed as follows:

For each factor associated with NSSI, quantitative findings—including correlation coefficients, ORs, regression coefficients, sample sizes and direction of association (positive/negative/no effect)—will be extracted and reported descriptively. Meta-analysis will not be conducted; quantitative results will serve solely to illustrate general patterns of association between factors and NSSI.

Subsequently, qualitative findings (themes, researchers’ interpretations and participant quotations) will be analysed to explain how and why these factors influence behaviour and to elucidate lived experiences of adolescents and young adults.

During the integration step, quantitative patterns (association strength/direction) and qualitative insights (mechanistic explanations) will be combined to produce an integrated statement for each factor—that is, a concise explanation of how and under what conditions the factor relates to NSSI.

The strength of evidence for each factor will be rated as strong, moderate or weak based on the number of studies, study design types and coherence of quantitative and qualitative evidence.

To enhance credibility and reduce bias, two independent reviewers will conduct thematic analysis. Discrepancies will be resolved through discussion and consultation with a third reviewer. In addition, findings will be validated in a feedback session with two supervisors specialising in adolescent and youth mental health, and their input will be incorporated into the final synthesis.

Stage 6: collation, summarisation and reporting of results

This final stage involves systematically organising, analysing and presenting the findings to produce a structured overview of the mapped evidence. Reporting will adhere to the PRISMA-ScR guidelines and the JBI methodology for scoping reviews.

The process will involve:

1. Descriptive summary: Study characteristics (design, sample, methodology) will be tabulated.

2. Content categorisation: Identified psychosocial factors will be organised into tables based on the integrated theoretical framework (Bronfenbrenner’s ecological levels and Nock’s functional model).

3. Comparative analysis: Patterns of factors will be analysed across age groups (adolescents vs young adults) and, where data permit, by sex.

4. Conceptual mapping: A diagram will illustrate hypothesised pathways and interactions among factors across different ecological levels.

The results will be reported in a final manuscript containing:

• A PRISMA flow diagram.

• A table of study characteristics and methodological quality (assessed via MMAT).

• Separate tables synthesising evidence for intrapersonal and interpersonal/ecological factors.

• A conceptual map integrating the findings within the theoretical framework.

• A discussion interpreting the findings, identifying key patterns and highlighting gaps in the evidence.

• Conclusions with implications for future research, clinical practice and public health policy in Iran.

• Supplementary files detailing the search strategies, data extraction forms and coding framework to ensure transparency and reproducibility.

Timeline

Study dates and the anticipated timeline are shown in table 5. Database searches were completed between 1 October and 15 October. Title/abstract screening, full-text review, data extraction and analysis are planned as indicated in the table.

Table 5. Anticipated schedule of activities.

Stage/task	Start date	End date	Status (completed/planned)
Design of research question and protocol	1 September 2025	30 September 2025	Completed
Literature search (databases+grey literature)	1 October 2025	15 October 2025	Completed
Title/abstract screening	15 October 2025	31 December 2025	Planned
Full-text retrieval and screening	1 January 2026	15 January 2026	Planned
Data charting/extraction	15 January 2026	1 February 2026	Planned
Thematic synthesis and narrative integration	1 February 2026	12 February 2026	Planned
Stakeholder consultation/validation	12 February 2026	17 February 2026	Planned
Manuscript drafting (results and tables)	17 February 2026	27 February 2026	Planned
Submission to journal	27 February 2026	1 March 2026	Planned

Note: dates are approximate and subject to change.

Ethical considerations

This study was conducted in accordance with ethical research principles and received ethical approval (Code: IR.UM.REC.1404.282) from the Iran National Committee for Ethics in Biomedical Research. The following considerations were upheld:

1. Adherence to scientific integrity, including accurate referencing and the avoidance of plagiarism.

2. Use of non-stigmatising and neutral language in reporting and discussing the results.

3. No requirement for obtaining informed consent, as the research used already published data and sources.

Patient and public involvement

Patients and/or the public will not be involved in the design, conduct, reporting or dissemination plans of this research.

Data availability

The data-extraction template and the detailed search strategies are publicly available in Figshare (10.6084 /m9.figshare.30840749).³⁷