Background: The objective of this study was to determine whether older adults with first-ever onset of depression after age 60 years (late onset depression, LOD) have smaller frontal lobes than elderly patients with early-onset depression (EOD) and aged controls.
Method: Twenty-seven subjects with LOD, 24 with EOD and 37 controls underwent volumetric MRI to determine right and left frontal lobe volumes and total brain volume.
Results: The right frontal volume of subjects with LOD was 8.0% and 5.6% smaller than that of patients with EOD (P < 0.01) and controls (NS) respectively. Volume of the left frontal lobe was not significantly different from EOD or controls. All analyses were adjusted for age, gender and total brain volume. Unlike controls and those with EOD, patients with LOD did not display a significant positive correlation between cognitive scores and total brain, left frontal or right frontal volumes.
Conclusion: LOD is associated with right frontal lobe atrophy and loss of the correlation between cognitive performance and brain volume. This adds support to the fronto-striatal hypothesis of depression and suggests that structural brain changes have a particular role in cases of LOD.