[Experimental psychological study of changes in the mental activity of schizophrenic patients with different degrees of expression of the defect].

Changes in mental activity related predominantly to one of the principal characteristics of the defect developing in schizophrenia, i.e. a decrease in mental activity, were studied by a complex of experimental psychological techniques designed to gain a better insight into the processes of memory and attention. A comparative study of groups of schizophrenic patients differing by the severity of the defect produced data characterizing the time-course of changes in mnemonic activity and voluntary attention due to defect aggravation and to the growth of a decrease in mental activity--the level of voluntary regulation and spontaneous activity.