Hypofrontality in schizophrenia: distributed dysfunctional circuits in neuroleptic-naïve patients.
BACKGROUND
There have been reports that patients with schizophrenia have decreased metabolic activity in prefrontal cortex. However, findings have been confounded by medication effects, chronic illness, and difficulties of measurement. We aimed to address these problems by examination of cerebral blood flow with positron emission tomography (PET).


METHODS
We studied 17 neuroleptic-naïve patients at the early stages of illness by means of image analysis and statistical methods that can detect abnormalities at the gyral level.


RESULTS
An initial omnibus test with a randomisation analysis indicated that patients differed from normal controls at the 0.06 level. In the follow-up analysis, three separate prefrontal regions had decreased perfusion (lateral, orbital, medial), as well as regions in inferior temporal and parietal cortex that are known to be anatomically connected. Regions with increased perfusion were also identified (eg, thalamus, cerebellum, retrosplenial cingulate), which suggests an imbalance in distributed cortical and subcortical circuits.


CONCLUSIONS
These distributed dysfunctional circuits may form the neural basis of schizophrenia through cognitive impairment of the brain, which prevents it from processing input efficiently and producing output effectively, thereby leading to symptoms such as hallucinations, delusions, and loss of volition.
Andreasen
N C
NC
Mental Health Clinical Research Centre, University of Iowa College of Medicine, Iowa City, USA.
O'Leary
D S
DS
Flaum
M
M
Nopoulos
P
P
Watkins
G L
GL
Boles Ponto
L L
LL
Hichwa
R D
RD
D000328:Adult; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D017397:Prefrontal Cortex / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000503:physiopathology; D012559:Schizophrenia / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D014055:Tomography, Emission-Computed