Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (866 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Unconscious process used by an individual or a group of individuals in order to cope with impulses, feelings or ideas which are not acceptable at their conscious level; various types include reaction formation, projection and self reversal.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Mechanisms, Defense.
Where it fits in the MeSH classification
- Broader topics
- Behavior and Behavior Mechanisms
- Narrower topics
- Acting Out; Denial, Psychological; Displacement, Psychological; Fantasy; Helplessness, Learned; Identification, Psychological; Information Avoidance; Perceptual Defense; Procrastination; Projection; Rationalization; Regression, Psychology; Repression, Psychology; Sublimation, Psychological
Research landscape
PubMed indexes 57,638 records tagged with the MeSH heading “Defense Mechanisms” (counts retrieved 2026-10-31). 8,839 of them (15.3%) were published from 2020 onward, and the busiest period so far is through 1999 with 26,623 records.
Reviews account for 4,979 records (8.6%) and meta-analyses for 215. Randomized controlled trials number 775 (1.3%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 26,623 |
| 2000-2009 | 10,147 |
| 2010-2019 | 12,029 |
| 2020 onward | 8,839 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 4,979 | 8.6% |
| Meta-analyses | 215 | 0.4% |
| Randomized controlled trials | 775 | 1.3% |
Method: PubMed query "Defense Mechanisms"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in psychiatry and psychology
Research on mental health and behaviour relies on questionnaires, interviews and rating scales rather than physical measurements, so how a condition was defined and measured shapes every result. Many studies are observational or small, placebo responses can be large, and findings in one group or culture may not carry over to another. Nothing on this page is advice about diagnosis or treatment; anyone worried about their mental health should talk to a qualified clinician. Check how outcomes were measured, who took part and how long they were followed.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Men's Mental Health Matters: The Impact of Traditional Masculinity Norms on Men's Willingness to Seek Mental Health Support; a Systematic Review of Literature | 2025 | Systematic review Design not recorded in structured metadata | 34 | cc by PMID 40421591 · DOI · PMC12117241 |
| Mental health help-seeking among Korean men: the influence of stigma, masculine norms, and face | 2025 | Research article Design not recorded in structured metadata | 10 | cc by PMID 40317029 · DOI · PMC12046740 |
| Sex/gender entanglement: A problem of knots and buckets | 2025 | Review article Design not recorded in structured metadata | 6 | cc by PMID 41168807 · DOI · PMC12577278 |
| Exploring the Intersection of Gender Identity and Eating Behaviours in Gender-Diverse Populations | 2026 | Research article Design not recorded in structured metadata | 4 | cc by PMID 41205200 · DOI · PMC13048733 |
Men's Mental Health Matters: The Impact of Traditional Masculinity Norms on Men's Willingness to Seek Mental Health Support; a Systematic Review of Literature [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Men's mental health is a focus area for improving population health worldwide.
- Closing excerpt
- Traditional masculinity norms significantly deter men from seeking mental health support, highlighting the need for culturally sensitive interventions that address these barriers.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (212 words)
Men's mental health is a focus area for improving population health worldwide. Traditional masculine norms among men have been reported to make them more susceptible to mental health issues. This study aims to review existing literature on how traditional masculinity norms influence men's willingness to seek mental health support. This review followed stages of systematic review. The review search was initiated in February 2024. The search process was conducted on electronic databases such as PubMed, PsycINFO, Science Direct, and Google Scholar to identify relevant studies published in English between 2000 and 2024. The search terms included "traditional masculinity norms," "men's mental health," "help-seeking behavior," and "barriers to mental health care." Studies were selected based on their relevance to the topic. The inclusion criteria were studies focusing on adult men and examining the relationship between traditional masculinity norms and mental health help-seeking behaviors. Exclusion criteria included studies focusing on children, adolescents, or women and nonempirical articles. Data extraction covered study details, design, population characteristics, and key findings. This study included 47 relevant studies. Two key themes emerged, namely: masculinity and mental health (impact on mental health); and barriers to seeking help. Traditional masculinity norms significantly deter men from seeking mental health support, highlighting the need for culturally sensitive interventions that address these barriers.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 40421591 · DOI · PMC12117241
Mental health help-seeking among Korean men: the influence of stigma, masculine norms, and face [2]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundPrevious studies have found that Asians and men are more susceptible to the stigma and stereotypes associated with mental illness.
- Closing excerpt
- The ultimate goal is to foster a social environment that encourages open discussion about mental illness, masculinity, and Asian values.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (194 words)
BackgroundPrevious studies have found that Asians and men are more susceptible to the stigma and stereotypes associated with mental illness. This social perception makes it difficult for Korean men to seek professional psychological help even when they desperately need it. The primary objectives of this study were to investigate barriers to mental health help-seeking among Korean men and to identify the role of sociocultural factors.MethodsA total of 341 Korean men aged 19 to 59 years participated in an online survey, which included questionnaires on loss of face, self-stigma of seeking help, attitudes toward seeking professional psychological help, and conformity to masculine norms. Structural Equation Modeling was used to explore the relationships among these variables.ResultsThe results revealed that loss of face indirectly affected attitudes toward seeking professional psychological help (ATSPPH) through its mediating effect on self-stigma. Loss of face did not directly influence ATSPPH. Furthermore, conformity to masculine norms negatively affected ATSPPH, and self-stigma mediated this relationship.ConclusionThese findings highlight the importance of understanding the influence of sociocultural factors in encouraging Korean men to seek help. The ultimate goal is to foster a social environment that encourages open discussion about mental illness, masculinity, and Asian values.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 40317029 · DOI · PMC12046740
Sex/gender entanglement: A problem of knots and buckets [3]
Abstract reading summary — source excerpts
- Opening excerpt
- When used as variables in biomedical research, sex and gender can be difficult to operationalize and measure.
- Closing excerpt
- In addition, we advocate for attention to variation within sex/gender, which is more informative in investigations of mechanism than comparing means across sex/gender categories.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (267 words)
When used as variables in biomedical research, sex and gender can be difficult to operationalize and measure. Questions have arisen about whether either category is stable or causally meaningful in a research context. Here, we discuss some of the limitations of using both or even one of these categories in correlational or experimental work. We argue that attempting to draw a distinction between sex and gender can reignite the nature/nurture debate, inadvertently bringing outdated metaphors and assumptions about innateness and causation into our research. Many researchers, including ourselves, have described sex and gender as separate collections of causal factors (which we describe as a "bucket" metaphor) or as entangled (a "knot" metaphor). Because they regard sex and gender as conceptually separable and internally consistent, such metaphors have limited value for understanding the drivers of diversity in our data. Rather than continuing to reify sex and gender as distinct buckets or threads of explanatory variables, we call for deconstruction of these categories by focusing instead on clearly operationalized, instantiating variables that researchers can manipulate or measure. Our proposed approach differs from recent, similar calls in that we are not suggesting the exclusion of a sex/gender category from statistical models; instead, we recommend keeping it-not as a representation of biological reality, but as a tool used under a careful set of assumptions. We provide example datasets to illustrate how a sex/gender category can, when thoughtfully operationalized, be used to improve statistical rigor and inferential precision. In addition, we advocate for attention to variation within sex/gender, which is more informative in investigations of mechanism than comparing means across sex/gender categories.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41168807 · DOI · PMC12577278
Exploring the Intersection of Gender Identity and Eating Behaviours in Gender-Diverse Populations [4]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundGender-diverse individuals are at elevated risk for disordered eating, shaped by body dissatisfaction, gender dysphoria, and minority stress.
- Closing excerpt
- Clinicians should consider how masculinity- and femininity-linked eating patterns shape assessment and intervention.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (193 words)
BackgroundGender-diverse individuals are at elevated risk for disordered eating, shaped by body dissatisfaction, gender dysphoria, and minority stress. The roles of gender identity and expression, however, remain underexplored in clinical samples. This study examined how self-perceived masculinity, femininity, and gender variance relate to eating behaviours in gender-diverse adults seeking gender-affirming care.MethodsEighty-four adults assigned female (n = 50) or male (n = 34) at birth were recruited from a regional gender incongruence clinic. Participants self-identified as male (n = 44), female (n = 30), or non-binary (n = 10); 36 were receiving gender-affirming hormone therapy (GAHT). They completed the Three-Factor Eating Questionnaire (TFEQ) and the Gender Variance Scale (GVS), assessing masculinity, femininity, and deviation from cisnormative expectations. Regression models tested associations between gender traits and eating behaviours.ResultsMasculinity was positively associated with cognitive restraint, while femininity correlated with emotional and uncontrolled eating. Gender variance was not significantly related to TFEQ; however, exploratory analyses suggested a modest quadratic trend with dysregulated eating. Eating behaviours did not differ by GAHT status.ConclusionsGender expression, more than gender variance, appears to influence eating behaviours in gender-diverse individuals. Clinicians should consider how masculinity- and femininity-linked eating patterns shape assessment and intervention.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41205200 · DOI · PMC13048733
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Gender differences in depression in representative national samples: Meta-analyses of diagnoses and symptoms [5]
- Research article Gender differences in emotion expression in children: a meta-analytic review [6]
- Research article Emotion Regulation Strategies in Depressive and Anxiety Symptoms in Youth: A Meta-Analytic Review [7]
- Research article A meta-analytic review of sex differences in facial expression processing and their development in infants, children, and adolescents [8]
- Research article Systematic review and meta-analysis of prevalence studies in transsexualism [9]
- Research article Assessing and Addressing Cardiovascular Health in People Who Are Transgender and Gender Diverse: A Scientific Statement From the American Heart Association [10]
References
- Mokhwelepa LW, Sumbane GO. Men's Mental Health Matters: The Impact of Traditional Masculinity Norms on Men's Willingness to Seek Mental Health Support; a Systematic Review of Literature. . 2025. PMID 40421591 · DOI · PMC12117241
- Kim S, Kim D. Mental health help-seeking among Korean men: the influence of stigma, masculine norms, and face. . 2025. PMID 40317029 · DOI · PMC12046740
- Maney DL, Duchesne A, Grossi G. Sex/gender entanglement: A problem of knots and buckets. . 2025. PMID 41168807 · DOI · PMC12577278
- Meneguzzo P, Biscaro M, Vozzi L, Bonato M, Scala A, Miscioscia M, et al.. Exploring the Intersection of Gender Identity and Eating Behaviours in Gender-Diverse Populations. . 2026. PMID 41205200 · DOI · PMC13048733
- Salk RH, Hyde JS, Abramson LY. Gender differences in depression in representative national samples: Meta-analyses of diagnoses and symptoms. Psychol Bull. 2017. PMID 28447828 · DOI · PMC5532074
- Chaplin TM, Aldao A. Gender differences in emotion expression in children: a meta-analytic review. Psychol Bull. 2013. PMID 23231534 · DOI · PMC3597769
- Schäfer JÖ, Naumann E, Holmes EA, Tuschen-Caffier B, Samson AC. Emotion Regulation Strategies in Depressive and Anxiety Symptoms in Youth: A Meta-Analytic Review. J Youth Adolesc. 2017. PMID 27734198 · DOI
- McClure EB. A meta-analytic review of sex differences in facial expression processing and their development in infants, children, and adolescents. Psychol Bull. 2000. PMID 10825784 · DOI
- Arcelus J, Bouman WP, Van Den Noortgate W, Claes L, Witcomb G, Fernandez-Aranda F. Systematic review and meta-analysis of prevalence studies in transsexualism. Eur Psychiatry. 2015. PMID 26021270 · DOI
- Streed CG, Beach LB, Caceres BA, Dowshen NL, Moreau KL, Mukherjee M, et al.. Assessing and Addressing Cardiovascular Health in People Who Are Transgender and Gender Diverse: A Scientific Statement From the American Heart Association. Circulation. 2021. PMID 34235936 · DOI · PMC8638087
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-11-04; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-11-04.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.