Age-Related Alterations in Gray Matter Microstructure in Older People With Remitted Major Depression at Risk for Dementia

PACt-MD Study Group

Research output: Contribution to journalArticlepeer-review


Background: Major depressive disorder (MDD) in late life is a risk factor for mild cognitive impairment (MCI) and Alzheimer's disease. However, studies of gray matter changes have produced varied estimates of which structures are implicated in MDD and dementia. Changes in gray matter volume and cortical thickness are macrostructural measures for the microstructural processes of free water accumulation and dendritic spine loss. Methods: We conducted multishell diffusion imaging to assess gray matter microstructure in 244 older adults with remitted MDD (n = 44), MCI (n = 115), remitted MDD+MCI (n = 61), or without psychiatric disorders or cognitive impairment (healthy control participants; n = 24). We estimated measures related to neurite density, orientation dispersion, and free water (isotropic volume fraction) using a biophysically plausible model (neurite orientation dispersion and density imaging). Results: Results showed that increasing age was correlated with an increase in isotropic volume fraction and a decrease in orientation dispersion index, which is consistent with neuropathology dendritic loss. In addition, this relationship between age and increased isotropic volume fraction was more disrupted in the MCI group than in the remitted MDD or healthy control groups. However, the association between age and orientation dispersion index was similar for all 3 groups. Conclusions: The findings suggest that the neurite orientation dispersion and density imaging measures could be used to identify biological risk factors for Alzheimer's disease, signifying both conventional neurodegeneration observed with MCI and dendritic loss seen in MDD.

Original languageEnglish
Pages (from-to)374-384
Number of pages11
JournalBiological Psychiatry Global Open Science
Issue number1
StatePublished - Jan 2024


  • Corticolimbic circuit
  • Dementia
  • Diffusion-weighted imaging
  • Fractional anisotropy
  • Frontal-executive circuit
  • Geriatric
  • Gray matter
  • MRI
  • Major depressive disorder
  • Mild cognitive impairment
  • Structural covariance
  • T1-weighted image


Dive into the research topics of 'Age-Related Alterations in Gray Matter Microstructure in Older People With Remitted Major Depression at Risk for Dementia'. Together they form a unique fingerprint.

Cite this