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: 3 complete abstracts (653 words), 9 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
A major affective disorder marked by severe mood swings (manic or major depressive episodes) and a tendency to remission and recurrence.
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: Bipolar Disorders; Disorder, Bipolar; Bipolar Mood Disorder; Bipolar Mood Disorders; Disorder, Bipolar Mood; Mood Disorder, Bipolar; Manic Depression; Depression, Manic.
Where it fits in the MeSH classification
- Broader topics
- Bipolar and Related Disorders
Research landscape
PubMed indexes 49,477 records tagged with the MeSH heading “Bipolar Disorder” (counts retrieved 2026-10-31). 9,142 of them (18.5%) were published from 2020 onward, and the busiest period so far is 2010-2019 with 15,192 records.
Reviews account for 7,766 records (15.7%) and meta-analyses for 1,093. Randomized controlled trials number 1,866 (3.8%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 14,537 |
| 2000-2009 | 10,606 |
| 2010-2019 | 15,192 |
| 2020 onward | 9,142 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 7,766 | 15.7% |
| Meta-analyses | 1,093 | 2.2% |
| Randomized controlled trials | 1,866 | 3.8% |
Method: PubMed query "Bipolar Disorder"[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 |
|---|---|---|---|---|
| Functional heterogeneity in non-suicidal self-injury across psychiatric disorders: neural and psychosocial correlates | 2026 | Research article Design not recorded in structured metadata | 6 | cc by PMID 41495020 · DOI · PMC12873407 |
| Sleep in Early Psychosis and Bipolar Disorder: Preliminary Results on Actigraphic and Self-Reported Markers of Vulnerability | 2026 | Research article Design not recorded in structured metadata | 5 | cc by PMID 41804931 · DOI · PMC12973353 |
| Distinguishing different psychiatric disorders using DDx-PRS | 2026 | Research article Design not recorded in structured metadata | 4 | cc by PMID 42625058 · DOI · PMC13559851 |
Functional heterogeneity in non-suicidal self-injury across psychiatric disorders: neural and psychosocial correlates [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Non-suicidal self-injury (NSSI) is a common behavior among adolescents, particularly within psychiatric populations.
- Closing excerpt
- Treatments targeting emotion regulation may benefit all subtypes, individuals with prominent social-related motivations may additionally require interventions aimed at improving interpersonal functioning.
- 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 (244 words)
Non-suicidal self-injury (NSSI) is a common behavior among adolescents, particularly within psychiatric populations. While neurobiological and psychosocial risk factors have been extensively studied, the mechanisms underlying NSSI's heterogeneity remain unclear. This study investigated 304 hospitalized adolescents/young adults (16-25 years) with NSSI and comorbid psychiatric diagnoses (major depressive disorder [MDD], bipolar disorder [BD], eating disorders [ED]) using psychological assessments and resting-state fMRI data from 163 participants. Orthogonal projection non-negative matrix factorization of Ottawa Self-Injury Inventory responses identified two latent factors: self-related factor and social-related factor. The self-related factor correlated with amygdala-centered cortico-limbic emotional regulation networks and predominated in affective disorders (MDD/BD), while the social-related factor linked to frontoparietal cognitive control and frontotemporal social cognition networks, particularly in ED. Fuzzy C-means clustering revealed three NSSI functional subtypes, independent of diagnostic categories: self-subtype primarily driven by self-related functions, social-subtype influenced by both self-related and social-related functions with greater exposure to psychosocial risks, and non-specific subtype characterized by mixed motivations. No subtype was exclusively driven by social-related functions. The "self-social" dual-dimensional framework with distinct neural mechanisms demonstrated subtype-specific profiles in functional connectivity, psychosocial risk exposure, and clinical features. Self-related mechanisms primarily engaged emotional regulation circuits, whereas social-related mechanisms emphasize the role of psychosocial risk factors and cognitive-emotional circuits. These findings provide neural evidence for the functional heterogeneity of NSSI and highlight the need for personalized interventions. Treatments targeting emotion regulation may benefit all subtypes, individuals with prominent social-related motivations may additionally require interventions aimed at improving interpersonal functioning.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41495020 · DOI · PMC12873407
Sleep in Early Psychosis and Bipolar Disorder: Preliminary Results on Actigraphic and Self-Reported Markers of Vulnerability [2]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundSleep disturbances are common in the early stages of psychosis and bipolar disorder and are increasingly regarded as transdiagnostic risk factors for symptom severity and suicidality.
- Closing excerpt
- Routine evaluation of both subjective and objective sleep may serve as early indicators of vulnerability and guide intervention strategies in severe mental illness.
- 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 (230 words)
BackgroundSleep disturbances are common in the early stages of psychosis and bipolar disorder and are increasingly regarded as transdiagnostic risk factors for symptom severity and suicidality. However, few studies have simultaneously examined both subjective and objective sleep changes during this early illness phase.MethodsThis cross-sectional study included patients within 12 months of the onset of psychosis or bipolar disorder and matched healthy controls. Patients completed standardised questionnaires including the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Beck Depression Inventory (BDI), Mood Disorder Questionnaire (MDQ) and Prodromal Questionnaire-16 (PQ-16). Actigraphy was recorded for seven consecutive nights in both groups.ResultsTwenty patients (11 with psychosis, 9 with bipolar disorder) and 20 healthy controls were assessed. Most patients reported poor sleep quality (70%), depressive symptoms (60%) and suicidal thoughts (65%). Poor sleep quality was strongly linked to depressive symptoms (r = 0.76) and prodromal features (r = 0.69). Actigraphy showed reduced total sleep time in patients compared to controls (388 vs. 449 min) and longer sleep latency in bipolar patients than in those with psychosis (161 vs. 80 min).ConclusionSleep disturbances are common during the first year of psychosis and bipolar disorder. Subjective sleep issues are closely linked to depression, prodromal psychotic symptoms and suicidal thoughts, while actigraphy shows disorder-specific differences. Routine evaluation of both subjective and objective sleep may serve as early indicators of vulnerability and guide intervention strategies in severe mental illness.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41804931 · DOI · PMC12973353
Distinguishing different psychiatric disorders using DDx-PRS [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Despite great progress on case-control polygenic prediction, an unmet need remains for a method that genetically distinguishes clinically related disorders (e.
- Closing excerpt
- True diagnosis probabilities in the top deciles of predicted diagnosis probabilities were considerably larger than prior baseline probabilities, implying appreciable potential for clinical utility in certain settings.
- 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 (179 words)
Despite great progress on case-control polygenic prediction, an unmet need remains for a method that genetically distinguishes clinically related disorders (e.g., schizophrenia (SCZ) versus bipolar disorder (BIP) versus major depressive disorder (MDD) versus controls). We introduce differential diagnosis-polygenic risk score (DDx-PRS), which jointly estimates the posterior probabilities of each diagnostic category (e.g., SCZ = 50%, BIP = 25%, MDD = 15%, control = 10%) by modeling variance-covariance structure across disorders, leveraging case-control polygenic risk scores and prior clinical probabilities for each diagnostic category. We applied DDx-PRS to Psychiatric Genomics Consortium SCZ, BIP, MDD and control data, including summary-level training data from three case-control genome-wide association studies (n = 41,917-173,140 cases; total n = 1,048,683) and held-out test data from different cohorts with equal numbers for each diagnostic category (total n = 11,460). DDx-PRS was well calibrated and well powered (consistent with simulations) and produced comparable results to methods that require tuning data. True diagnosis probabilities in the top deciles of predicted diagnosis probabilities were considerably larger than prior baseline probabilities, implying appreciable potential for clinical utility in certain settings.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42625058 · DOI · PMC13559851
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 Genome-wide association study of more than 40,000 bipolar disorder cases provides new insights into the underlying biology [4]
- Research article Genome-wide association study identifies 30 loci associated with bipolar disorder [5]
- Research article Air Pollution (Particulate Matter) Exposure and Associations with Depression, Anxiety, Bipolar, Psychosis and Suicide Risk: A Systematic Review and Meta-Analysis [6]
- Research article Psychotropic medication non-adherence and its associated factors among patients with major psychiatric disorders: a systematic review and meta-analysis [7]
- Research article Depression pathophysiology, risk prediction of recurrence and comorbid psychiatric disorders using genome-wide analyses [8]
- Research article Common and distinct patterns of intrinsic brain activity alterations in major depression and bipolar disorder: voxel-based meta-analysis [9]
Full-text reviews on EvidenceLib
Open-access review articles about this topic, reproduced in full with authors, licence and references.
The Role of the Gut Microbiota in the Development and Progression of Major Depressive and Bipolar Disorder
Tom Knuesel, M. Hasan Mohajeri · Nutrients 2021 · CC BY 4.0
References
- Li M, Xiao Y, Ge Y, Yan H, Li X, Yue W, et al.. Functional heterogeneity in non-suicidal self-injury across psychiatric disorders: neural and psychosocial correlates. . 2026. PMID 41495020 · DOI · PMC12873407
- Baldini V, Iannucci F, Venezia N, Pasquino F, Gnazzo M, de Ronchi D, et al.. Sleep in Early Psychosis and Bipolar Disorder: Preliminary Results on Actigraphic and Self-Reported Markers of Vulnerability. . 2026. PMID 41804931 · DOI · PMC12973353
- Peyrot WJ, Panagiotaropoulou G, Olde Loohuis LM, Adams MJ, Andreassen OA, Awasthi S, et al.. Distinguishing different psychiatric disorders using DDx-PRS. . 2026. PMID 42625058 · DOI · PMC13559851
- Mullins N, Forstner AJ, O'Connell KS, Coombes B, Coleman JRI, Qiao Z, et al.. Genome-wide association study of more than 40,000 bipolar disorder cases provides new insights into the underlying biology. Nat Genet. 2021. PMID 34002096 · DOI · PMC8192451
- Stahl EA, Breen G, Forstner AJ, McQuillin A, Ripke S, Trubetskoy V, et al.. Genome-wide association study identifies 30 loci associated with bipolar disorder. Nat Genet. 2019. PMID 31043756 · DOI · PMC6956732
- Braithwaite I, Zhang S, Kirkbride JB, Osborn DPJ, Hayes JF. Air Pollution (Particulate Matter) Exposure and Associations with Depression, Anxiety, Bipolar, Psychosis and Suicide Risk: A Systematic Review and Meta-Analysis. Environ Health Perspect. 2019. PMID 31850801 · DOI · PMC6957283
- Semahegn A, Torpey K, Manu A, Assefa N, Tesfaye G, Ankomah A. Psychotropic medication non-adherence and its associated factors among patients with major psychiatric disorders: a systematic review and meta-analysis. Syst Rev. 2020. PMID 31948489 · DOI · PMC6966860
- Als TD, Kurki MI, Grove J, Voloudakis G, Therrien K, Tasanko E, et al.. Depression pathophysiology, risk prediction of recurrence and comorbid psychiatric disorders using genome-wide analyses. Nat Med. 2023. PMID 37464041 · DOI · PMC10839245
- Gong J, Wang J, Qiu S, Chen P, Luo Z, Wang J, et al.. Common and distinct patterns of intrinsic brain activity alterations in major depression and bipolar disorder: voxel-based meta-analysis. Transl Psychiatry. 2020. PMID 33077728 · DOI · PMC7573621
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.