The neurophysiological correlates of cognitive impairment in first-episode young male patients have been studied. The auditory evoked potentials in oddball paradigm were recorded in groups of patients stratified by predominance of certain symptoms as follows: catatonic symptoms (22 subjects), hallucinations and delusions (22) affective and delusions (24). The control group included 15 mentally healthy subjects. In the group with predominance of catatonic symptoms, the most marked slowing of N200 and P300 latency was found. In the group with predominance of hallucinations and delusions, the most topographically localized anomalies by P300 latency was observed. In the group with predominance of affective and delusions, the N200 slowing was almost absent, however the anomalies of N100 to non-target stimuli and P300 were most pronounced than in the other groups. These peculiarities of neurophysiological correlates of cognitive functions in each group of patients emphasize the importance of the physiological structure of the first episode for development of clinical pathology.