Sensory gating deficits assessed by the P50 event-related potential in subjects with schizotypal personality disorder

Objective: The schizophrenia spectrum includes individuals with schizophren ia, their relatives, and individuals with schizotypal personality disorder. Subjects in the schizophrenia spectrum have disorders of attention, cognit ion, and information processing. Attention and information processing can b e assessed by testing suppression of the P50 event-related potential; the a mplitude of the P50 wave is measured in response to each of two auditory cl icks. In normal subjects, the P50 wave following the second click is suppre ssed, or "gated." Schizophrenic patients and their relatives show less supp ression of the second P50 wave, Deficits in P50 suppression have high herit ability and show linkage to the alpha-7 subunit of the nicotinic cholinergi c receptor gene in families with schizophrenia, suggesting that deficits in P50 suppression are trait markers for gating abnormalities in schizophreni a spectrum subjects. Although schizotypal subjects have been shown to have deficits in sensorimotor gating as measured by prepulse inhibition, to the authors' knowledge P50 sensory gating in schizotypal personality disorder h as yet to be reported. Method: P50 suppression in 26 subjects with schizoty pal personality disorder and 23 normal subjects was assessed through audito ry conditioning and testing. Results: The subjects with schizotypal persona lity had significantly less P50 suppression than did the normal subjects. C onclusions: Subjects with schizotypal personality disorder may have trait-l inked sensory gating deficits similar to those in patients with schizophren ia and their relatives. Because these subjects may manifest sensory gating deficits without overt psychotic symptoms, it is likely that these deficits represent a core cognitive dysfunction of the schizophrenia spectrum.