A DATA-DRIVEN EXAMINATION OF APATHY AND DEPRESSIVE SYMPTOMS IN DEMENTIA WITH INDEPENDENT REPLICATION

ABSTRACT Introduction Apathy is one of the most common neuropsychiatric symptoms (NPS) and is associated with poor clinical outcomes. Research that helps define the apathy phenotype is urgently needed, particularly for clinical and biomarker studies. Methods We used latent class analysis (LCA) with two independent cohorts to understand how apathy and depression symptoms co-occur statistically. We further explored the relationship between latent class membership, demographics and the presence of other NPS. Results The LCA identified a 4-class solution (No Symptoms, Apathy, Depression, and Combined Apathy/Depression), reproducible over both cohorts, providing robust support for an apathy syndrome distinct from depression and confirming that an apathy/depression syndrome exists. Discussion Using a data-driven method, we show distinct and statistically meaningful co-occurrence of apathy and depressive symptoms. There was evidence that these classes have different clinical associations which may help inform diagnostic categories for research studies and clinical practice.