[Neurophysiological differentiation of personality disorders]

The neurophysiological objectification of intranosological differentiation of main clusters (schizoid/paranoid and hysterical/emotionally unstable) within the typology of personality disorders (PD), as well as the differentiation of schizoid/paranoid PD and schizophrenia.

Two groups of patients with PD participated in the study: PD1 - with schizoid/paranoid pattern (n=16), and PD2 - with hysterical/emotionally unstable pattern (n=18). The data were compared with the control group of healthy volunteers (n=86) and the group of schizophrenic patients (Sz, n=67). The analysis of four neurophysiological endophenotypes (measures of prepulse inhibition (PPI) of acoustic startle response and of P50 suppression, P300 amplitude, percentage of antisaccade errors) was carried out.

The decrease of PPI and P50 suppression (measures of sensorimotor and sensory gating) relative to the control group was found both for Sz (p<0.01) and PD1 (p<0.05) groups. The highest P300 amplitude was observed in the control group, while the lowest values were observed in the Sz group (p<0.001); the values of PD1 and PD2 groups were intermediate. In all clinical groups percent of antisaccade errors was significantly higher compared to the control group (Sz - p<0.001; PD1 - p<0.05; PD2 - p<0.01). However, the level of the fronto-central cortical activation during antisaccade performance (estimated by contingent negative variation amplitude) was significantly reduced only in the Sz group (p<0.01), which is consistent with the concept of «hypofrontality» in schizophrenia. The changes associated with increased emotional reactivity were found in PD2 group only (P300 amplitude frontal maximum, asymmetry of error percent in antisaccade task).

The study showed that two personality patterns in PD patients are related to the individual specificity of functional brain networks.