Authors

Kim JJ. Mohamed S. Andreasen NC. O'Leary DS. Watkins GL. Boles

Ponto LL. Hichwa RD.

 

Institution

Mental Health Clinical Research Center, Department of Psychiatry, University of Iowa Hospital, College of Medicine, Iowa City, USA.

 

Title

Regional neural dysfunctions in chronic schizophrenia studied with positron emission tomography.

Source

American Journal of Psychiatry. 157(4):542-8, 2000 Apr.

 

Abstract

OBJECTIVE: Whether chronicity of illness produces progressive neural

abnormality is an important question in current schizophrenia research.

Positron emission tomography (PET) offers an opportunity to visualize and

measure blood flow in vivo to address this issue. The authors previously

compared healthy volunteers with neuroleptic-naive patients experiencing

their first episode of schizophrenia and reported that abnormalities in blood

flow, including lower flow in prefrontal regions and higher flow in the

thalamus and cerebellum, are present at the early stage of schizophrenic

illness. The goal of the present study was to measure blood flow with PET in

patients with chronic schizophrenia. METHOD: PET was used to examine regional

cerebral blood flow (rCBF) in 30 patients with chronic schizophrenia and 30

normal comparison subjects. To determine if the patterns of flow abnormality

in the patients with chronic schizophrenia were similar to those of patients

experiencing their first episode of schizophrenia, the same cognitive

condition was examined as in the earlier study. The patients with chronic

schizophrenia in the current study had been neuroleptic-free for at least 3

weeks. RESULTS: As in the authors' previous study, the chronically ill

patients showed lower flow in prefrontal areas and higher flow in thalamic

and cerebellar regions than normal comparison subjects, suggesting that a

similar neural dysfunction occurs in both first-episode and chronic

schizophrenia. CONCLUSIONS: rCBF abnormalities in patients with chronic

schizophrenia are not due to chronicity of illness or the effects of

medication. These results provide evidence that the primary neural

abnormalities in schizophrenia may occur in cortical, cerebellar, and

thalamic regions and that the dysfunction in these regions may explain the

"loosening of associations" that Bleuler considered to be the fundamental

cognitive phenotype of schizophrenia. These abnormalities can be

reconceptualized as "cognitive dysmetria."