Is there a CSF biomarker profile related to depression in elderly women?

In light of our previous observation of higher levels of cerebrospinal fluid (CSF) amyloid beta-42 (Aβ42) and CSF/serum albumin ratio in major depressive disorder (MDD), we analyzed two additional CSF biomarkers reflecting neurodegeneration—neurofilament protein light (NFL) and glial fibrillary acidic protein (GFAp)—in relationship to prevalent geriatric depression. Neuropsychiatric, physical, and lumbar puncture examinations, with DSM-III-R-based depression diagnoses and measurement of CSF levels of NFL and GFAp, were evaluated among a population-based sample of 78 elderly women (mean age, 73.9 ± 3.2 years) without dementia for at least 10 years after CSF collection. Eleven (13.1%) women had MDD, and higher levels of NFL compared with women without depression. A multivariate model including age, NFL, Aβ42 and the CSF/serum albumin ratio showed that each biomarker was independently and positively associated with MDD, and that this biomarker profile explained more variation in the model compared with single or combined biomarkers. A CSF profile with higher levels of NFL, Aβ42, and CSF/serum albumin ratio may indicate neuropathological and vascular events in depression etiology. This contrasts with the well-characterized pattern of low Aβ42, higher CSF/serum albumin ratio, and higher NFL in Alzheimer's disease.