The relationship between cognitive inhibition and psychotic symptoms

Cognitive models of schizophrenia have highlighted deficits of inhibitory a ttentional processes as central to the disorder. This has been investigated using "negative priming" (S. P. Tipper, 1985), with schizophrenia patients showing a reduction of negative priming in a number of studies. This study attempted to replicate these findings, but studied psychotic symptoms rath er than the broad diagnostic category of schizophrenia. Psychotic individua ls exhibiting positive symptoms were compared with asymptomatic psychiatric patients and with a normal control group. As predicted, the symptomatic gr oup failed to show the usual negative priming effect which was present in t he asymptomatic and normal groups. A modest bur significant correlation was found between negative priming and delusions. Neither diagnosis. nor affec tive or negative symptoms, nor chronicity, nor medication, was related to n egative priming. These data replicate previous findings that positive sympt oms are related to a reduction in cognitive inhibition, although considerab le variability was observed among the psychotic patients.