title: Psychophysiological differences in schizophrenics with and without delusional misidentification syndromes: a P300 study.
abstract: There is a debate on whether delusional misidentification syndromes (DMSs) and schizophrenia are distinct disorders. Information-processing deficits have been found in both. Since the P300 component of event-related potentials (ERPs) reflects attention and working memory (WM) mechanisms, the P300 elicited during a WM test was studied in schizophrenic patients with DMS in comparison to schizophrenic patients without DMS and controls. Nine schizophrenic patients with DMS, 11 without DMS and 11 healthy controls were tested with a computerized version of the digit span test of the Wechsler batteries. Auditory ERPs were measured during the anticipatory period of the test. P300 amplitude in prefrontal areas was found to be significantly reduced in schizophrenics without DMS and markedly less in DMS patients compared to controls. P300 latency in the central midline brain region was significantly prolonged in DMS patients compared to the other groups. Memory performance was significantly reduced in both patient groups as compared to healthy controls. The results may indicate abnormalities in both allocation of attentional resources and automatic orienting in schizophrenic patients with DSM. In contrast, even though schizophrenic patients without DMS exhibit partial similarities with patients suffering from DMS, they show excessive reduction of P300 amplitude located at the left frontal area. Future studies might clarify these issues.
authors.affiliation: Psychophysiology Laboratory, Department of Psychiatry, Eginition Hospital, Medical School, University of Athens, 74 Vas. Sophias Avenue, Athens 11528, Greece. panchris@otenet.gr
authors.forename: Charalabos
authors.initials: C
authors.lastname: Papageorgiou
authors.forename: Lefteris
authors.initials: L
authors.lastname: Lykouras
authors.forename: Basil
authors.initials: B
authors.lastname: Alevizos
authors.forename: Errikos
authors.initials: E
authors.lastname: Ventouras
authors.forename: Polyxeni
authors.initials: P
authors.lastname: Mourtzouchou
authors.forename: Nicolaos
authors.initials: N
authors.lastname: Uzunoglu
authors.forename: George N
authors.initials: GN
authors.lastname: Christodoulou
authors.forename: Andreas
authors.initials: A
authors.lastname: Rabavilas
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D003702:Delusions / Q000503:physiopathology* / Q000523:psychology*; D004569:Electroencephalography; D004585:Electrooculography; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000502:physiology; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology