Brain Amyloid Deposition in Late-Life Depression

Abstract

We read with great interest the recent article by Mackin et al. ( 1 Mackin R.S. Insel P.S. Landau S. Bickford D. Morin R. Rhodes E. et al. Late-life depression is associated with reduced cortical amyloid burden: Findings from the Alzheimer’s Disease Neuroimaging Initiative Depression Project. Biol Psychiatry. 2021; 89: 757-765 Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar ). This is an important contribution because it reverts the common belief that subjects with late-life depression (LLD) have increased brain amyloid beta (Aβ) deposition compared with cognitively healthy nondepressed (ND) control subjects. Indeed, the authors found that patients with LLD have less Aβ pathology than control subjects. Mackin et al. confirmed previous literature showing that this psychiatric population has impaired cognition and speculated that this may be due to Aβ-unrelated mechanisms. The study appears robust because it involved 238 subjects from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) Depression Project and ADNI database. However, we would like to point out some potential biases of the study that may have influenced the findings, at least in part. Late-Life Depression Is Associated With Reduced Cortical Amyloid Burden: Findings From the Alzheimer’s Disease Neuroimaging Initiative Depression ProjectBiological PsychiatryVol. 89Issue 8PreviewWe evaluated the role of cortical amyloid deposition as a factor contributing to memory dysfunction and increased risk of dementia associated with late-life depression (LLD). Full-Text PDF Reply to: Brain Amyloid Deposition in Late-Life DepressionBiological PsychiatryVol. 89Issue 8PreviewWe appreciate the comments of Pomara and Imbimbo (1) on our article (2). We found these comments to be thought-provoking and agree that these issues are important to clarify. Our colleagues initially raise concern that a difference in amyloid beta (Aβ) positron emission tomography (PET) standardized uptake value ratio (SUVR) between the nondepressed and late-life depression (LLD) groups was minimal (1.10 ± 0.16 vs. 1.06 ± 0.14; p = .02). However, a group difference of 0.04 with a residual standard deviation of 0.14 appears more than minimal. Full-Text PDF