White matter lesions on magnetic resonance imaging in late-life depression

Objectives: The aims of the present study were to identify the frequency and severity of white matter lesions on the magnetic resonance imaging (MRI) of major depressive disorders and depression caused by cerebrovascular diseases (CVD), to evaluate the relation with cerebrovascular risk factors, and finally to understand an important cause of late‐life depression. Methods: The MRI films of 32 patients over 50 years of age (15 men and 17 women) with major depressive disorders, 25 patients (17 men and eight women) with depression caused by CVD who had scores over 24 on the mini‐mental state examination, and 25 controls (six men and 19 women) were analyzed for white matter lesions according to the modified Fazekas criteria. The cerebrovascular risk factors including hypertension, arteriosclerosis, obesity, smoking, diabetes mellitus, thyroid function abnormalities, EKG abnormality and stroke were also assessed. Results: (i) The frequency of periventricular lesions or deep white matter lesions were significantly higher in patients with depression caused by CVD and major depressive disorders than in controls; (ii) the intracerebral hyperintensities or classical infarctions were prevalent in the frontal cortex (32.0%) and basal ganglia (40.0%); (iii) among cerebrovascular risk factors, stroke (P < 0.005), hypertension (P < 0.025), EKG abnormality (P < 0.005) and smoking (P < 0.05) were significantly prevalent in the patients with depression caused by CVD and major depressive disorders as compared with controls; and (iv) the severity of white matter lesions was significantly associated with the cerebrovascular risk factors (P < 0.005) in patients over 50 years of age with major depressive disorders. Conclusions: The white matter hyperintensities on brain MRI of patients with major depressive disorders over 50 years of age were significantly associated with cerebrovascular risk factors, which suggested a vascular origin of pathogenesis of late‐life depression.