Meta-analysis identifies protein associations with behavioral symptoms in dementia

Behavioral and psychological symptoms of dementia (BPSD) are common, profoundly troubling to patients and caregivers, and difficult to treat, yet their molecular underpinnings remain poorly understood. Here, we generated the first brain proteomic dataset with BPSD phenotyping, profiling the dorsolateral prefrontal cortex of 376 donors from three cohorts spanning nine BPSD domains assessed in life. Protein associations with BPSD were examined using complementary approaches - domain-specific BPSD, multi-domain BPSD, and latent factor modeling - and integrated via cross-cohort meta-analysis. Four proteins (NMT1, DCAKD, DNPH1, and HIBADH) were associated with anxiety in dementia and five proteins (ABL1, SAP18, PLXND1, CTRB2, and LDHD) with multi-domain BPSD or BPSD latent factors after adjusting for sex, age, and other covariates (FDR < 0.05). Additionally, eight protein co-expression networks were associated with BPSD across cohorts. These results link BPSD to dysregulation of synaptic signaling, protein folding, and humoral immune response, providing a molecular framework for therapeutic discovery.