Temporal pattern of dementia with lewy bodies diagnostic labels around electroconvulsive therapy: A nationwide claims-based study

Abstract

Background: Electroconvulsive therapy (ECT) is widely used for severe depression. Dementia with Lewy bodies (DLB) may initially present with depressive symptoms, and ECT may be administered in some patients during the course of the disease. However, the timing of DLB diagnosis in relation to ECT treatment has not been well characterized. Methods: We conducted a retrospective cohort study using a nationwide administrative claims database in Japan, including records from 564 acute care hospitals between April 2008 and March 2025. Analyses were restricted to patients with a mood disorder diagnosis (ICD-10 F30–F39) recorded in the same month as the first ECT session, and patients with both DLB and Alzheimer disease (AD) diagnostic codes were excluded. The primary analysis examined the timing of recorded DLB diagnostic labels relative to ECT initiation, with AD diagnoses analyzed as a comparator. Results: Among 3733 patients who underwent ECT, 71 met the analytic criteria for DLB. The median interval between ECT initiation and the first DLB diagnosis was 8 days prior to ECT initiation. Recorded DLB diagnostic labels occurred significantly more often within ±90 and ±180 days of ECT initiation than AD diagnoses, whereas AD diagnoses were distributed more broadly across the observation period. Conclusion: Recorded DLB diagnostic labels showed a distinct temporal pattern around ECT initiation. Clinical evaluation associated with ECT may facilitate recognition of underlying DLB in patients presenting with severe psychiatric symptoms. Clinicians should remain attentive to evolving DLB when treating late-life treatment-resistant mood disorders with ECT, as recognition of DLB may occur several years after treatment initiation.