The prognostic significance of distinct psychosis symptom profiles in dementia: A cohort study using linked electronic health records

Background Psychotic symptoms in dementia overall are associated with poorer outcomes, but the prognostic significance of different symptom profiles remains unclear. We aimed to evaluate the prognostic significance of distinct psychosis profiles in a large dementia cohort. Methods We used de-identified electronic health records from a large South London mental health and dementia care provider. The cohort included 21,108 patients with dementia diagnosed between 2008 and 2022. Psychosis was identified after dementia diagnosis and classified as hallucinations only (H + D-), delusions only (H-D+), co-occurring hallucinations and delusions (H + D+), or no psychosis (H-D-). Cox regression models estimated hazard ratios (HRs) for mortality, psychiatric admission, and general hospital admission comparing the different hallucination/delusions combinations with no psychosis. Logistic regression estimated odds ratios (ORs) for care home admission. Multivariate models were adjusted for sociodemographic factors, cognition, dementia subtype, mental health diagnoses, pharmacotherapy, and physical comorbidity. Results Psychotic symptoms were present in 34.8% of patients with dementia. In fully adjusted models, H + D+ showed the most consistent associations across all outcomes: mortality (aHR: 1.10, 95% CI: 1.04–1.17), general hospital admission (aHR: 1.13, 95% CI: 1.06–1.19), psychiatric admission (aHR: 2.15, 95% CI: 1.71–2.70), and long-term care admission (aOR: 1.23, 95% CI: 1.04–1.46). H + D− was associated with increases in mortality (aHR: 1.08, 95% CI: 1.03–1.13), general hospital admission (aHR: 1.06, 95% CI: 1.02–1.11), and psychiatric admission (aHR: 1.28, 95% CI: 1.02–1.61), but not long-term care ademission. H − D+ was associated only with psychiatric admission (aHR: 1.41, 95% CI: 1.07–1.85). Conclusions The prognostic significance of psychosis in dementia differs by symptom profile. Combined hallucinations and delusions identify a particularly severe phenotype associated with consistently poorer outcomes and greater service need.