Do atypical antipsychotics fail to exert cognitive sparing effects?
The aim of the study was to investigate patterns of the P600 component of event-related potentials (ERPs) elicited during a working memory test in 16 male schizophrenic patients experiencing auditory hallucinations before and after treatment with clozapine and olanzapine, and 13 male normal subjects matched for age and educational level. Before treatment, patients showed significantly reduced P600 amplitudes on the right parietal region compared with controls, and when in remission also showed significantly reduced P600 amplitudes located on the right parietal and temporofrontal areas, compared both to themselves before treatment and to normal controls. The patient's memory performance before and after treatment remained significantly lower than that of healthy controls. These findings may indicate that auditory hallucinations in schizophrenia are associated with impaired synchronization of the processes related to target detection, as reflected by the P600. The present study also casts doubts regarding the cognitive sparing effect of atypical antipsychotics, despite the fact that they mediate symptom improvement.
Papageorgiou
Charalabos
C
Department of Psychiatry, Egnition Hospital, University of Athens, Athens, Greece. panchris@otenet.gr
Oulis
Panayiotis
P
Vasios
Christos
C
Matsopoulos
George K
GK
Uzunoglu
Nikolaos
N
Rabavilas
Andreas
A
Christodoulou
George N
GN
D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001569:Benzodiazepines; D001921:Brain / Q000503:physiopathology; D003024:Clozapine / Q000627:therapeutic use*; D003071:Cognition / Q000187:drug effects*; D004311:Double-Blind Method; D005072:Evoked Potentials, Auditory / Q000187:drug effects; D006212:Hallucinations / Q000209:etiology; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects; D000077152:Olanzapine; D010890:Pirenzepine / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D011569:Psychiatric Status Rating Scales; D012016:Reference Values; D012559:Schizophrenia / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D012565:Schizophrenic Psychology
D014150:Antipsychotic Agents; D001569:Benzodiazepines; D010890:Pirenzepine; D003024:Clozapine; D000077152:Olanzapine