Suicidal ideation in dementia: associations with neuropsychiatric symptoms and subtype diagnosis

Objectives: To investigate factors associated with suicidal ideation (SI) around the time of dementia diagnosis. We hypothesised relatively preserved cognition, co-occurring physical and psychiatric disorders, functional impairments, and dementia diagnosis subtype would be associated with a higher risk of SI. Design: Cross-sectional study using routinely collected electronic mental healthcare records. Setting: National Health Service secondary mental healthcare services in South London, UK, serving a population of over 1.36 million residents. Participants: Patients who received a diagnosis of dementia (Alzheimer's, vascular, mixed Alzheimer's/vascular, or dementia with Lewy bodies) between 1 Nov 2007-31 Oct 2021: 18,252 people were identified during the observation period. Measurements: A natural language processing algorithm was used to identify recorded clinician recording of SI around the time of dementia diagnosis. Sociodemographic and clinical characteristics were also measured around the time of diagnosis. We compared people diagnosed with non-Alzheimer's dementia to those with Alzheimer's and used statistical models to adjust for putative confounders. Results: 15.1% of patients had recorded SI, which was more common in dementia with Lewy bodies compared to other dementia diagnoses studied. After adjusting for sociodemographic and clinical factors, SI was more frequent in those with depression and dementia with Lewy bodies and less common in those with impaired activities of daily living and in vascular dementia. Agitated behavior and hallucinations were not associated with SI in the final model. Conclusions: Our findings highlight the importance of identifying and treating depressive symptoms in people with dementia and the need for further research into under-researched dementia subtypes.