Structural Abnormality on Brain Magnetic Resonance Imaging in Late-onset Major Depressive Disorder

The purpose of this study was to examine the structural abnormalities of patients with late-onset major depressive disorder using brain magnetic resonance imaging (MRI) and to assess clinical correlates of these structural abnormalities. Thirty-seven elderly patients with DSM-IV major depressive disorder that first occurred after the age of 50 years, and 18 control subjects without depression were recruited. All participants underwent comprehensive psychiatric assessment and cerebral MRI. Brain ventricular and sulcal sizes and white matter hyperintensities were assessed visually. Relative to control subjects, patients with late-life major depressive disorder showed more severe brain atrophy (p = 0.043) and white matter hyperintensities (p = 0.024), especially in the periventricular area (p = 0.012). Over 60% of the patient group had significant brain MRI hyperintensities. White matter hyperintensity was correlated with later onset of depressive illness (r = 0.49, p = 0.002) among patients. Brain atrophy and white matter hyperintensities are prevalent in patients with late-onset major depressive disorders. These two abnormalities may represent different pathophysiologic processes of depressive disorders. White matter hyperintensities may be predisposing factors for late-onset major depressive disorder.