Clinical Trajectory of Late-Onset Delusional Disorder Toward Evolving Dementia With Lewy Bodies.
Hiroshige Fujishiro, Kazuhiro Takeda, Kuniyuki Iwata-Endo et al.
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Case in brief
The report revisited four clinicopathological cases in which late-onset delusional disorder was the initial manifestation of Lewy body disease. Delusions began in the patients’ 50s or 60s, often with reluctance to seek psychiatric care; eventual hospitalisation and poor antipsychotic tolerance were recurring features. Dementia emerged later, accompanied by core features of dementia with Lewy bodies (DLB). The authors propose that persistent delusions may occur with relatively restricted Lewy pathology before widespread cortical involvement, while relative preservation of substantia nigra neurons may explain the early absence of parkinsonism.
What made this case unusual
The cases suggest an exceptionally prolonged prodromal period: delusions began decades before dementia, despite DLB commonly presenting in the mid-70s or later. Early delusions could occur without parkinsonism.
Diagnostic / clinical pearl
In an older adult with persistent late-onset delusions, the absence of early dementia or parkinsonism does not exclude an evolving Lewy body disease trajectory.
Why it matters
Distinguishing late-onset delusional disorder from broader late-onset psychosis may help define a more homogeneous group for future study of prodromal Lewy body disease.