Leukoencephalopathy in patients diagnosed as major depressive

Abstract

Bradley et al. (1984) reported that 30% of patients over the age of 60 demonstrate leukoencephalopathy or patchy, deep white matter lesions (PWML) of abnormal signal intensity on T2 weighted images on magnetic resonance imaging (MRI). These foci, which are not seen in normal individuals below the age of 45 (George et al. 1986b), are believed to be a function of the late stage of the aging process. With MRI, areas of deep white matter foci resemble those seen in known cerebral infarction (Erkinjuntti et al. 1984) and are reported to correspond to areas of moderate to severe arteriolar hyalinization and rarefaction on pathological examination (George et al. 1986a). The overall perspective on the clinical significance of PWML has yet to be determined. In patients with Alzheimer’s disease, the prevalence and severity of PWML is increased (Bent-~wad~i et al. 1985; George et al. 1986b). Prevalence of PWML of 36.67% was found in patients with Alzheimer’s disease at our medical center (mean age 64.3 years) (Heyman et al. 1986). Post (1962) and Roth (1986) suggested that the increased prevalence and severity of depressive illness and suicide in middle and late life is due to subtle cerebral (primarily vascular) changes correlated with aging. As PWML may reflect early and subtle alterations in cerebral function, we decided to assess the relationship, if any, between the occurrence of PWML (leuk~nceph~opa~y) and depression, especially depression in middle and late life. We also examined the relationship between PWML and early-onset affective disorder (i.e., onset of first episode before the age of 45) and affective disorder that first occurs after the age of 45. We used 45 years as the cutoff for the study because of the report that PWML are not seen in normal individuals below the age of 45 (George et al. 1986b). We also examined the hypothesis that the incidence of PWML would be higher in patients with the first episode of affective disorder above age 45 than in those patients above 45 with affective disorder that started before the age of 45. Such a finding would suggest that PWML may be causally related to depression in some of these individuals.