[Evoked potentials N200/P300 disorders and clinical phenotype in Cuban families with paranoid schizophrenia: a family-based association study].

INTRODUCTION

N200 and P300 event-related evoked potentials provide sensitive measurements of sensory and cognitive function and have been used to study information processing in patients with schizophrenia and their unaffected first-degree relatives. Reduced amplitude and increased latency of N200 and P300 potentials have been consistently reported in schizophrenia. Thus, event-related evoked potentials abnormalities are promising possible biological markers for genetic vulnerability to schizophrenia.

OBJECTIVE

To assess the association of changes in latency, amplitude and topographic distribution of potentials N200 and P300 of patients with paranoid schizophrenia and their healthy first-degree relatives, in families with schizophrenia multiplex.

METHODOLOGY: We measured latency and amplitude of the N200 and P300 component of evoked potentials using an auditory odd-ball paradigm in 25 schizophrenic patients (probands) from 60 families multiply affected with paranoid schizophrenia, 23 of their non-schizophrenic first-degree relatives and 25 unrelated healthy controls, through a study of family association.

RESULTS

Schizophrenic patients and their relatives showed significant latency prolongation and amplitude reduction of the N200 and P300 waves compared to controls. Left-temporal as compared to right-temporal N200 and P300 were significantly smaller in schizophrenic patients and their non-schizophrenic first-degree relatives than in controls. Our results suggest that event-related evoked potentials abnormalities may serve as markers of genetic vulnerability in schizophrenia.

CONCLUSIONS

Confirming results of other researchers, this present study suggests that latency prolongation and amplitude reduction of the N200 and P300 waves and an altered topography at temporal sites may be a trait “marker” of paranoid schizophrenia.