Dementia as a complication of schizophrenia

Objectives-Cognitive impairment is known to occur in schizophrenia, and may be marked in institutionalised patients. The aim of this study was to dete rmine whether it ever warrants an additional diagnosis of dementia. Methods-A population of chronic schizophrenic patients who were aged 65 or younger and showed no organic risk factors for dementia were screened for p resence of disorientation. Any showing this underwent neuropsychological te sting, physical investigations, and structural and functional neuroimaging. Information about day to day cognitive function was also obtained from car ers. Results-Eight patients aged 28 to 64 were identified who showed disorientat ion; in all cases this was accompanied by general intellectual impairment a nd objective evidence of a dementia syndrome. The patients' schizophrenic s ymptoms were unexceptional and did not seem sufficient to account for their cognitive impairment. Neuropsychological testing disclosed relative sparin g of visual and visuospatial function and language syntax, but pervasive de ficits in memory and executive function. Brain CT demonstrated only minor a bnormalities but most of the patients showed frontal or temporal hypoperfus ion on SPECT. Conclusions-Dementia in schizophrenia seems to be a real entity with a neur opsychological signature similar to that of frontotemporal dementia. Functi onal but not structural imaging abnormalities may also be characteristic.