Background: A number of meta-analytic reviews of structural brain imaging studies have shown that multiple subtle brain abnormalities are consistently found in schizophrenia. However, quantitative reviews till now published have included mainly studies performed on chronic schizophrenic patients but have failed to provide clear information on specific, possibly different, findings in first-episode schizophrenia.
Methods: We performed a systematic search for MRI studies that reported quantitative measurements of volumes of brain regions in first-episode schizophrenic patients and in healthy controls. Twelve meta-analyses were performed for 6 cerebral regions.
Results: Twenty-one studies were identified as suitable for analysis. Significant overall effect sizes were demonstrated for lateral and third ventricular volume increase, and for volume reduction of whole brain and hippocampus, but not for temporal lobe, amygdala and total intracranial volumes.
Conclusions: The available literature data strongly indicate that some brain abnormalities are already present in first-episode schizophrenic patients. However, unlike the results of published meta-analyses conducted primarily on samples of chronic schizophrenic patients, the present study did not confirm a significant reduction of temporal lobe or amygdala volumes in first-episode schizophrenia. These findings support the hypothesis of different patterns of involvement of various cerebral areas over the time course of schizophrenia.