Perseverative structuring of responses by schizophrenic and affective disorder patients.

Some theoretical implications from a CNS stimulation model of psychosis were tested by analysing the response patterns of schizophrenic (N = 34), affective disorder patients (N = 18), schizoid personality disorder patients (N = 9), neurotic patients (N = 9) and normal controls (N = 34) on a visual two-choice task with reinforcement. The subjects were required to press a left and right button in order to cause a cross (+) to appear on the monitor screen above one of the buttons. Certain subsequences of right and left presses were required in order for the cross to appear, and a coin-reinforcement was delivered on a variable-ratio schedule with respect to the cross condition. An analysis of structured responding in categories: one-side greater than 6, switching (RLRL), 2-1 switching (RRL) and double alternations (RRLL), revealed that the schizophrenic and affective disorder patients were significantly more perseverative in these response categories than normal controls, schizoid or neurotic patients. The last three subject groups were not significantly different from each other. The majority of the schizophrenics and all four manic patients showed the highest percentage of responding in one sided responses greater than 6, switching and 2-1 switching. Normal control subjects showed more varied response patterns with responses in double, triple and quadruple alternations and other combinations. The results are seen to support a CNS stimulation, behavioral competition model of psychosis.