Experimental Studies of the Mental Speed of Schizophrenics

It has been clinically observed that psychiatric patients in general (6, 11) and schizophrenic patients in particular (1, 4) show abnormalities of mental speed, being “retarded” or slower than normals on many measures. Confirmatory evidence on this point is to be found but much of the early work on speed of schizophrenic reactivity used measures of speed of motor performance (12, 13) or of reaction time under various conditions (6), ignoring more fundamental slowness of thought processes. The present studies are concentrated on the recent finding that schizophrenics show abnormally slow mental speed measured in a problem-solving situation (4, 18, 19). The aim of the investigation was to discover the exact conditions under which this abnormality appears, and, thence, by manipulating the experimental conditions, to be able to bring speed of mental functioning under experimental control. This paper describes the attempt to bring speed under control by means of drugs. A second paper (2) deals with the effect of practice upon mental speed.