Schizoaffective disorder: Evidence for reversed cerebral asymmetry

Background: Schizoaffective disorder is one of the most severe of the affec tive psychoses, but its pathophysiology is poorly understood, Because cereb ral lateralization may be disturbed in psychotic disorders generally, studi es examining cerebral asymmetry may improve understanding of the neurobiolo gy specific to schizoaffective disorder. This study examines cerebral later alization in this patient population using magnetic source localization. Methods: We studied 16 subjects with schizoaffective disorder and 16 contro ls. Magnetic source localization was used to identify the location of the 2 0 msec latency somatosensory evoked field component (M20), Results: In control subjects, the source location was further anterior in t he right hemisphere, The subjects with schizoaffective disorder were revers e lateralized, Conclusions: The findings of a reversed asymmetry of the M20 in patients wi th schizoaffective disorder suggest an anatomical shift in the placement of the post central gyrus in this disorder, compatible with a disorder of cer ebral lateralization. Whether this finding converges or diverges with measu rement of the M20 in other psychotic disorders will require further investi gation (C) 1999 Society of Biological Psychiatry.