Late-onset paranoid psychosis as a distinct clinicopathologic entity: Magnetic resonance imaging data in elderly patients with paranoid psychosis of late onset and schizophrenia of early onset

Objective: The aim of this study is to equalize the influence of age-relate d changes and to test the hypothesis that specific structural brain changes are mediating the development of unique clinical features in late-onset pa ranoid psychosis (LOPP). Background: Findings of unique white matter lesion s have been recently described in patients with LOPP. These findings have n ot been consistent, however, when age-matched normal subjects have been use d as a control group. Method: Magnetic resonance imaging data were compared in 13 patients with LOPP, mean age 66.33, and 35 elderly patients with ear ly-onset paranoid schizophrenia (PSCH), mean age 63.89. Patients in the LOP P group differed from the PSCH group by the mild degree or absence of negat ive symptoms, the absence of formal thought disorders, and by prevalence of female patients. Results: Analysis of the magnetic resonance imaging data revealed statistically significant differences between the LOPP and PSCH gr oups. White matter hyperintensity was almost threefold more frequent in LOP P than in PSCH groups, 69.2% versus 22.9% respectively. Ventricular enlarge ment and cortical atrophy were more frequent in the PSCH group, reaching, f or moderate to severe abnormalities, 28.6% for ventricular enlargement and 22.9% for cortical atrophy; moderate to severe abnormalities were absent in all 13 patients of the LOPP group. Conclusions: These data point to the po ssibility that late-onset paranoid psychosis is a distinct clinicopathologi cal entity, with white matter hyperintensity mediating the development of L OPP in a significant percentage of the cases. The vascular origin of white matter lesions in LOPP is suggested.