Time-linked impairment in schizophrenic reaction time performance.

Reports on the disruptive influence of uncertain visual probe stimuli on schizophrenic reaction time performance as a function of both the time since the onset of the probe stimuli and the pathology level of the Ss. Two studies were conducted, using 32 process schizophrenics, 16 reactive schizophrenics, 16 nonschizophrenic patients (alcoholic, immature personality, and depression diagnoses), and 16 normal controls. Mean ages of Ss ranged from 28.2 to 37.1 yrs. Probe trials were imbedded within standard series of regular reaction time trials. Both process and reactive schizophrenics were impaired by this stimulation on trials with only a 1-sec preparatory interval. Process schizophrenics showed impairment at the longest (9-sec) trials following recovery at midrange durations. The midrange recovery and long trial impairment of the process schizophrenics was a pattern strongly related to degree of pathology. The same U-shaped pattern—early and late impairment with intermediate recovery—and a similar relationship of the reaction time pattern to pathology level were found again in a 2nd sample of process schizophrenics who were given less intense visual stimulation on the probe trials. The U-shaped patterns obtained for the process schizophrenics in both studies are thought to reflect inadequate modulation of inhibitory controls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)