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The endophenotype concept is considered as theoretical basis for the study of pathobiological mechanisms of schizophrenia and for the development of the complex of instrumental diagnostic methods. The contemporary state of the problem and the most significant results of the study of three neurophysiological schizophrenia endophenotypes are presented in the review: P50 auditory evoked potential suppression, prepulse inhibition of the startle reflex and antisaccade task. The current understanding of the underlying neurophysiological and neurochemical mechanisms is described for each measure. The results of the association studies of neurophysiological endophenotypes with the relevant to schizophrenia genes' polymorphisms are laid down. High degree of independence of the considered endophenotypes is demonstrated. Taking into account the data on relatively low specificity of each endophenotype to schizophrenia compared to other mental disturbances the authors pay special attention to the model of multivariate endophenotype as a scientific and diagnostic tool.

Prepulse modification of acoustic startle reaction (ASR) was studied in patients with schizophrenia and healthy controls according to the protocol recommended by the Consortium on the genetics of schizophrenia. Patients displayed the reduced ASR magnitude of prepulse inhibition (PPI) and increased startle latency prepulse facilitation (PPF) at 60 ms lead interval. The ASR amplitude PPF at 2500 ms lead interval was also impaired in patients. Effects of the recent head trauma and psychoactive drug experience on the ASR prepulse modification were different in patients and controls. The high baseline amplitude and short ASR latency in patients were correlated with the excitation level measured with the PANSS (item P4) whereas the PPF reduction was correlated with the high total score on the PANSS positive subscale. These results suggest the possibility of using ASR prepulse modification in clinical neurophysiology.