The association between major depressive disorder, plasma biomarkers of Alzheimer's disease, and mild behavioral impairment among older adults.

INTRODUCTION

Plasma biomarkers and mild behavioral impairment (MBI) are associated with dementia risk, but their relationships with major depressive disorder (MDD) are understudied. This study aimed to examine associations between plasma biomarkers of Alzheimer's disease (AD) and MBI among older adults with and without MDD.

METHODS

Older adults aged ≥65 were recruited from longitudinal studies of depression and AD (n = 330) in the DRIVES Project. Variables included Clinical Dementia Rating (CDR) scale, Mild Behavioral Impariment Checklist (MBI-C), Neuropsychiatric Inventory Questionnaire, Area Deprivation Index, and plasma biomarkers (amyloid beta [Aβ] 42/Aβ40, phosphorylated tau (p-tau) 181/non-p-tau181, p-tau217/non-p-tau217). Logistic regression assessed associations among MDD, plasma amyloid positivity, antidepressant use, and MBI.

RESULTS

Older adults with MDD were more likely to endorse MBI. After adjustment, Aβ42/Aβ40 and p-tau217/np-tau217 positivity were associated with MBI among those with MDD but not among those without.

DISCUSSION: Neuropsychatric symptoms (NPS) and biomarkers are AD risk factors. Early identification of MDD may reduce NPS severity, and tracking NPS onset, duration, and frequency is crucial for AD management.