Delusional themes are more varied than previously assumed: a comprehensive systematic review and Meta-analysis
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BACKGROUND AND HYPOTHESIS: Delusions are classified into themes but the range of themes reported in the literature has never been examined and the extent to which they differ in prevalence, or relate to clinical characteristics or cultural variation, remains poorly understood. STUDY DESIGN: We identified studies reporting delusional theme prevalence in adults with psychosis and completed two multivariate, multilevel, random-effects meta-analyses: one including data from structured assessment scales only and another also including data from ad hoc and clinical assessments to include themes from a wider range of countries and contexts. Sensitivity and meta-regression analyses examined the association with clinical and methodological variables. Analysis code and open data are available online. PROSPERO registration (CRD42019151889). STUDY RESULTS: A total of 155 studies from 37 countries met inclusion criteria. The meta-analysis of data from structured assessments included 110 studies and 173 920 patients. A total of 21 themes were identified from "persecutory/paranoid" (57.33%, 53.75-60.88) to "primary" (5.18%, 1.07-11.55). The meta-analysis of all data included 155 studies and 240 901 patients. Thirty-seven themes were identified, from "persecutory/paranoid" (57.39%, 54.38-60.37) to "made impulse" (4.90%, 0.87-11.26). Ad hoc theme classifications were more common in non-Western contexts. Including these did not substantially alter heterogeneity but increased interaction with cultural clusters. There was no evidence of publication bias or association with risk of bias rating. CONCLUSIONS: We report the first comprehensive meta-analysis of delusional themes. Many commonly reported themes are not included in standard classifications. Relationship to culture was modest but more present when not relying solely on established scales.
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This pattern is largely consistent with findings in other communities, where persecution and grandiosity are often reported as the most common delusional experiences both in patient populations and in general healthy individuals.
“This is largely consistent with findings in other communities, where persecution and grandiosity are often reported as the most common delusional experiences both in patient populations (Grunfeld et al., 2023; Pappa et al., 2025; Picardi et al., 2018) and in general healthy individuals (Freeman, 2006).”
From “I was trying to save the world”: delusion-like ideation and associated impacts reported by Western practitioners of Buddhist meditation (2025) · cites this paper as Pappa et al., 2025
The Discussion (page unavailable) says persecutory/paranoid delusions appear to be the most common theme. The Synthesis of Results reports increased prevalence of grandiose delusions in bipolar disorder, but the retrieved passages do not establish grandiosity as one of the most common themes across patient populations. This citation is attached to the patient-populations clause, not the separate claim about healthy individuals. (LLM, conf=0.84)
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- Authors
- Pappa, E., Baah, F., Lynch, J., Shiel, L., Blackman, G., Raihani, N., & Bell, V.
- Affiliations
- University College London (GB)
- South London and Maudsley NHS Foundation Trust (GB)
- Oxleas NHS Foundation Trust (GB)
- Oxford Health NHS Foundation Trust (GB)
- University of Auckland (NZ)
- Corresponding author
- Bell, Vaughan
- Venue
- Schizophrenia Bulletin
- Publisher
- Oxford University Press (OUP)
- Published
- 2025-01-23
- Volume
- 51
- Issue
- 3
- Pages
- 637-645
- ISSN
- 0586-7614 (ISSN-L)
- 1745-1701
- PMC
- PMC12061659
- OpenAlex
- W4406738818
- Cited by
- 19
- References
- 41
- Citations by year
- 2026: 10 · 2025: 9
- FWCI
- 3.37
- Type
- journal article
- Language
- en
- Open access
- hybrid
- doi.org
- Licence
- Locations
- Schizophrenia Bulletin (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- Funders
- Royal Society University Research
- Topics
- Health Sciences › Medicine › Psychiatry and Mental health › Schizophrenia research and treatment
- Social Sciences › Arts and Humanities › Philosophy › Mental Health and Psychiatry
- Life Sciences › Neuroscience › Cognitive Neuroscience › Hallucinations in medical conditions
- Keywords
- delusions
- MeSH terms
- Delusions, Humans, Psychotic Disorders, Schizophrenia
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