OBJECTIVE: To determine EEG markers of depression severity and clarify the brain mechanisms of heboid depression by identifying relationships between clinical and neurophysiological parameters in female adolescents with heboid depression. MATERIAL AND METHODS: A clinical-neurophysiological study of 25 female adolescents, aged 16-25 years, mean age 18.7±2.6 years, with heboid depression (ICD-10 items F31.3-F31.4, F34.0) was carried out. The severity of depressive disorders during hospitalization varied from mild to severe - the HDRS-17 total score ranged from 12 to 37 points (average 26.4±6.5 points). To assess the functional state of the brain, a multichannel EEG recording was performed in a state of calm wakefulness with closed eyes (for 2-3 minutes). EEG was recorded in 16 leads: F7, F3, F4, F8, T3, C3, Cz, C4, T4, T5, P3, Pz, P4, T6, O1 and O2. Data analysis was carried out using descriptive and nonparametric statistics programs from the IBM SPSS Statistics, v.22 package. RESULTS: Differences in the EEG of patients from the norm were detected in the alpha frequency range, SpM values of the alpha2 subrange (9-11 Hz) were statistically significantly lower in the frontal areas (in the left frontal lead F3 p=0.021, in the right frontal lead F4 p=0.006). The patients did not have «highly coherent¼ (Coh >0.80) interhemispheric connections between the frontal-central-anterotemporal regions of the left and right hemispheres in the frequency range of the alpha-rhythm (8-13 Hz). The following correlations (p≤0.05) were revealed: the values of the HDRS-17 total score were positively correlated with the spectral power values of theta1 (4-6 Hz) and theta2 (6-8 Hz) EEG frequency subranges only in the frontal, central and midtemporal leads from the right hemisphere (F4, C4, T4). CONCLUSION: In patients with heboid depression, there is a functional «uncoupling¼ of the frontal-central-anterior-temporal areas of the right and left hemispheres of the brain. It is possible that such a «dissociation¼ and a relatively large activation of the anterior parts of the left rather than the right hemisphere play a role in the weak control of impulsive delinquent behavior in patients with heboid depression. The identified atypical features of the EEG spatial organization and correlations of the EEG frequency structure with clinical parameters are consistent with the atypical clinical picture of heboid depression.