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


METHODS
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."
Kim
J J
JJ
Mental Health Clinical Research Center, Department of Psychiatry, University of Iowa Hospital, College of Medicine, Iowa City, USA.
Mohamed
S
S
Andreasen
N C
NC
O'Leary
D S
DS
Watkins
G L
GL
Boles Ponto
L L
LL
Hichwa
R D
RD
D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002531:Cerebellum / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D010104:Oxygen Radioisotopes; D017397:Prefrontal Cortex / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D012039:Regional Blood Flow; D012559:Schizophrenia / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D013788:Thalamus / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D014055:Tomography, Emission-Computed; D014867:Water
D010104:Oxygen Radioisotopes; D014867:Water