{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T14:23:58Z","timestamp":1785421438794,"version":"3.56.0"},"reference-count":55,"publisher":"Cambridge University Press (CUP)","license":[{"start":{"date-parts":[[2026,5,15]],"date-time":"2026-05-15T00:00:00Z","timestamp":1778803200000},"content-version":"unspecified","delay-in-days":134,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["cambridge.org"],"crossmark-restriction":true},"short-container-title":["Psychol. Med."],"published-print":{"date-parts":[[2026]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>The nosological status and psychopathology of delusional disorder have been a subject of debate since Kraepelin distinguished it from schizophrenia and affective psychoses. Contemporary diagnostic manuals define delusional disorder primarily by the presence of delusions, offering limited guidance for its differentiation from schizophrenia. Notably, DSM-5 introduced a major, seemingly unexplained change by allowing bizarre delusions in delusional disorder, contrary to ICD-11, prior DSM editions, and classical descriptions. This narrative review revisits the seminal works of six classical authors (Kraepelin, Jaspers, Kretschmer, S\u00e9rieux and Capgras, and De Cl\u00e9rambault), who shaped the concept of delusional disorder (paranoia), and their detailed clinical cases of the disorder. All considered delusional disorder to be an independent psychotic disorder, characterized by chronic, systematized, nonbizarre delusions, preservation of personality, and minimal hallucinations, with a largely intact experiential framework outside of the delusional theme. Additional features such as delusional misinterpretations, illusions, and false memories were also emphasized in the classical literature. We examined these authors\u2019 clinical cases of delusional disorder for the presence of delusional features characteristic of schizophrenia (delusional mood, first-rank symptoms, autistic-solipsistic delusions, and double bookkeeping), which index alterations in the structure of experience rather than mere delusional content. Such delusions were rarely found in the classical clinical cases of delusional disorder. Our findings highlight psychopathological distinctions between delusional disorder and schizophrenia, suggesting that schizophrenia involves a qualitative alteration of the experiential framework that is absent in delusional disorder. These findings raise concerns about the validity of the DSM-5 change, allowing bizarre delusions in delusional disorder.<\/jats:p>","DOI":"10.1017\/s0033291726103663","type":"journal-article","created":{"date-parts":[[2026,5,15]],"date-time":"2026-05-15T09:37:04Z","timestamp":1778837824000},"update-policy":"https:\/\/doi.org\/10.1017\/policypage","source":"Crossref","is-referenced-by-count":0,"title":["Delusional disorder and its differentiation from schizophrenia: A narrative review"],"prefix":"10.1017","volume":"56","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-2855-0796","authenticated-orcid":false,"given":"Daniele","family":"Rossi Grauenfels","sequence":"first","affiliation":[{"name":"AUSL di Bologna: Azienda Unit\u00e0 Sanitaria Locale di Bologna"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2103-7318","authenticated-orcid":false,"given":"Mads Gram","family":"Henriksen","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05exy9t05","id-type":"ROR","asserted-by":"publisher"}],"name":"Central and Western Zealand Hospital"},{"id":[{"id":"https:\/\/ror.org\/035b05819","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Copenhagen"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2492-9124","authenticated-orcid":false,"given":"Julie","family":"Nordgaard","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05exy9t05","id-type":"ROR","asserted-by":"publisher"}],"name":"Central and Western Zealand Hospital"},{"id":[{"id":"https:\/\/ror.org\/035b05819","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Copenhagen"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"56","published-online":{"date-parts":[[2026,5,15]]},"reference":[{"key":"S0033291726103663_r9","volume-title":"Affectivity, suggestibility, paranoia","author":"Bleuler","year":"1912"},{"key":"S0033291726103663_r41","first-page":"417","article-title":"La th\u00e9orie psychanalytique du d\u00e9lire","volume":"XXII","author":"Nacht","year":"1958","journal-title":"Revue Fran\u00e7aise de Psychanalyse, Tome"},{"key":"S0033291726103663_r37","doi-asserted-by":"crossref","first-page":"561","DOI":"10.1093\/schbul\/sbq125","article-title":"Delusional disorders \u2013 Are they simply paranoid schizophrenia?","volume":"38","author":"Marneros","year":"2012","journal-title":"Schizophrenia Bulletin"},{"key":"S0033291726103663_r45","doi-asserted-by":"crossref","first-page":"2829","DOI":"10.1017\/S0033291716001501","article-title":"Delusional disorder and schizophrenia: A comparative study across multiple domains","volume":"46","author":"Peralta","year":"2016","journal-title":"Psychological Medicine"},{"key":"S0033291726103663_r21","doi-asserted-by":"crossref","first-page":"3085","DOI":"10.1017\/S0033291715001051","article-title":"Delusional disorder and schizophrenia: A comparison of the neurocognitive and clinical characteristics in first-episode patients","volume":"45","author":"Hui","year":"2015","journal-title":"Psychological Medicine"},{"key":"S0033291726103663_r20","doi-asserted-by":"crossref","first-page":"1272833","DOI":"10.3389\/fpsyt.2023.1272833","article-title":"Age-matched versus non-age-matched comparison of clinical and functional differences between delusional disorder and schizophrenia: A systematic review","volume":"14","author":"Hui","year":"2023","journal-title":"Frontiers in Psychiatry"},{"key":"S0033291726103663_r10","volume-title":"Dementia praecox or the group of schizophrenias","author":"Bleuler","year":"1950"},{"key":"S0033291726103663_r4","volume-title":"Diagnostic and statistical manual of mental disorders: DSM-IV-TR","year":"2000"},{"key":"S0033291726103663_r49","volume-title":"Les folies raisonnantes. 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