Introduction Reduced hippocampal volume and increased prevalence of subcortical white matter lesions are associated with both recurrent early-onset depression (EOD) and late-onset depression (LOD). It is not clear whether these two factors differentially affect the age of first depression onset. Therefore we want to investigate the relationship between age of first depression onset and hippocampal volume with adjustment for subcortical white matter lesions.
Methods Magnetic Resonance Imaging (MRI) brain scans were used to compare hippocampal volumes and white matter lesions in age-matched female older patients (> 60 years) with recurrent early-onset depression and late-onset depression and healthy controls.
Results When comparing the three groups and adjusting for age, Mini-Mental State Examination score and total brain volume, total hippocampal volume was significantly smaller in patients with EOD compared to controls (5.6 ml versus 6.1 ml, p=0.04). Prevalence of larger subcortical white matter lesions was higher in patients with LOD compared to patients with EOD (47% versus 8%, p=0.002). Patients with LOD did not differ in hippocampal volume from patients with EOD and from controls.
Conclusions In late-life depression, age of first depression onset may distinguish between different independent neuropathologic mechanisms. A small hippocampus volume may be a neuranatomic marker of EOD depression and larger subcortical white matter lesions could be an intermediate between cerebrovascular disease and LOD.
- age of onset
- magnetic resonance imaging
- white matter lesions