Background : the combined form of psychopathologic diathesis is a special personality structure, capable of to transform into various manifest forms of psychiatric disorders. Neurophysiological features of this form of diathesis practically not studied from the point of view of interdisciplinary research methods research. The aim of study is to determine the neurofunctional basis underlying the clinical phenomenology of the indicated form of psychiatric diathesis. Participiants and methods: 2433 students (mean age 21,1 ± 3,9 yrs) were examined. Two main groups of 74 and 107 students were formed on the basis of the Abraham- Ferenczi-Szondi theory, each of them including a certain variant of the combined form of psychopathological diathesis. EEG recordings of 330 subjects (mean age 21,3 ± 3,7) from the normative HBI Database were used as a control group (CG). The main indicators studied were quantitative evaluation and comparison of the spectral power of the EEG of the respondents both between the main and control groups and with the indicators of neurofunctioning of individuals with various psychiatric pathologies obtained from the literature. Results : the main indicators of changes in the bioelectrical activity of the brain of the examined persons in comparison with the control group were a decrease in the power of practically all frequency ranges in the posterior regions of brain and an increase in the power of the high-frequency alpha rhythm in the associative zones of the cerebral cortex. Comparison of the bioelectrical activity indices of the two main groups of respondents among themselves allows us to characterize their EEG patterns as different, due to the fact that the brain systems providing their manifestations belong to the reciprocally functioning parts of the brain. Conclusions : the mentioned features of bioelectrical activity of the brain are the neurofunctional basis underlying the characteristic mental disorders, which are the manifest form of the combined psychopathological diathesis and determine the distinctive features of the phenomenology of its clinical picture. The division of the group of investigated persons into two subgroups according to the neuropsychoanalytic concept allows a more differentiated approach to the study of the combined form of psychopathological diathesis. This approach can be used in further scientific c research and allows expand diagnostic capabilities and therapy of this form of mental diathesis