Hemispheric asymmetry of frontal and temporal gray matter and age of onset in schizophrenia

Background: Investigators have reported lack of normal asymmetry of lateralization in some schizophrenic patients, as measured postmortem and by preference and/or performance. It has been suggested that this lack of asymmetry is related to early onset of schizophrenia. The present study extends the inquiry by magnetic resonance imaging (MRI) measurement of volumetric asymmetry. Methods: Hemispheric asymmetry of volume in regional gray matter was examined in 16 schizophrenic patients who had undergone MRI of brain volume. Results: Low levels of hemispheric asymmetry in the frontal and temporal areas were strongly associated with early onset of schizophrenia, the association with frontal volume being more marked than with temporal volume. No relationship was found in the other brain areas that were scanned. The findings were not artifacts of chronological age, nor of extreme scores in a small sample. Conclusions: These findings are consistent with the hypothesis that failure to develop asymmetry is an important component of the pathology underlying some forms of schizophrenia.