Schizophrenia--a brain disease? A critical review of structural and functional cerebral abnormality in the disorder.
BACKGROUND
With genetic and neurochemical findings pointing to a biological aetiology, considerable effort has been devoted to finding direct evidence of brain abnormality in schizophrenia.


METHODS
CT, MRI, post-mortem and functional imaging studies are reviewed to assess which structural and/or functional brain abnormalities have been consistently demonstrated.


RESULTS
The only well-established structural abnormality in schizophrenia is lateral ventricular enlargement; this is modest and there is a large overlap with the normal population. There is no consensus on the presence of any localised structural abnormality from MRI and post-mortem studies, but the most promising findings concern temporal lobe limbic structures. Hypofrontality is not a well-replicated finding in schizophrenia under resting conditions, but the evidence is stronger for a selective association with negative symptoms. A number of studies have found hypofrontality under conditions of neuropsychological task activation. However, findings in these studies are divided and a recent methodologically sophisticated study has failed to confirm it, although this study suggested a decoupling of prefrontal and temporal function.


CONCLUSIONS
Schizophrenia is characterised by minor structural abnormality which, in the case of lateral ventricular enlargement, may be better understood as a risk factor than a causative lesion. The functional imaging findings are not transparent but suggest that, as a disorder, schizophrenia shows complex alterations in regional patterns of activity rather than any simple deficit in prefrontal function.
Chua
S E
SE
Institute of Psychiatry, London.
McKenna
P J
PJ
D001921:Brain / Q000473:pathology / Q000503:physiopathology; D001925:Brain Damage, Chronic / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D001931:Brain Mapping; D003952:Diagnostic Imaging; D006801:Humans; D019965:Neurocognitive Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D011569:Psychiatric Status Rating Scales; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology*; D012565:Schizophrenic Psychology