Related resources
Search for item elsewhere
University researcher(s)
P300 alterations in schizophrenic patients experiencing auditory hallucinations.
Papageorgiou C, Oulis P, Vasios C, Kontopantelis E, Uzunoglu N, Rabavilas A, Christodoulou G
Eur Neuropsychopharmacol. 2004;14( 3):227-36.
Access to files
Full-text and supplementary files are not available from Manchester eScholar. Use our list of Related resources to find this item elsewhere. Alternatively, request a copy from the Library's Document supply service.
Abstract
RATIONALE: Attentional deficits have been implicated in the pathophysiology of auditory hallucinations in schizophrenia. Since the latency of the P300 component of event-related potentials (ERPs) is considered to be a sensitive measure of stimulus classification speed, while its amplitude-a measure of attentional resource allocation when memory updating is engaged, the present study focuses on the comparison of P300 between healthy subjects and schizophrenic patients experiencing auditory hallucinations and treated with clozapine and olanzapine. METHODS: The auditory P300 was assessed during the anticipatory period of a short memory test, in 16 male hallucinated schizophrenic patients and 13 male normal subjects matched for age and educational level. The patients were reexamined under identical conditions when their hallucinations had resolved following treatment with clozapine (8 patients) and olanzapine (8 patients). RESULTS: The patients with hallucinations exhibited significantly reduced P300 amplitude at leads Fp1, F3, (C3-T5)/2, F4, Cz and Fz, when compared to the normal controls and at leads Fp1, F3, F4, (C4-T6)/2, C4, P4, Cz and Fz when compared to themselves during the remission phase. However logistic regression models revealed that the most important leads, differentiating the patient group before treatment either with the healthy controls, or with itself after treatment, were that at the left temporoparietal and at the left prefrontal area. Memory performance of the patient group, even after treatment and in spite of its significant improvement, remained significantly less than that of healthy controls. both antipsychotic agents had similar effects on the p300 amplitude and memory performance. CONCLUSIONS: These findings indicate that auditory hallucinations in schizophrenia manifest abnormal aspects of attention, mediated by a distributed network involving or affecting the left temporoparietal and left prefrontal area. Additionally, the present study points to an improvement of attentional function in schizophrenic patients experiencing auditory hallucinations, both in the clozapine group but also in the olanzapine group.
Keyword(s)
Adult; Case-Control Studies; Comparative Study; Humans; Male; Neuropsychological Tests; Psychiatric Status Rating Scales; Research Support, Non-U.S. Gov't; complications: Schizophrenia; drug effects: Attention; drug effects: Event-Related Potentials, P300; drug effects: Reaction Time; drug therapy: Hallucinations; pharmacology: Antipsychotic Agents; pharmacology: Benzodiazepines; pharmacology: Clozapine; physiology: Memory, Short-Term