OBJECTIVE

To search for neurophysiological correlates of the characteristics of the brain functional state in patients with endogenous depression with an ultra-high risk of developing psychosis in comparison with EEG parameters of patients without symptoms of a risk of developing psychosis and patients who have suffered psychotic episode.

MATERIAL AND METHODS

The study included 92 female patients, aged 16—26 years, at the stage of remission, divided into three groups: with depression without symptoms of ultra-high risk of developing psychosis (group 1, n=42), with depression and attenuated psychotic symptoms, but without a history of a psychotic episode (group 2, n=32) and with depression that developed after experiencing a psychotic episode (group 3, n=18). In all patients, pre-treatment multichannel background EEG was recorded with spectral power analysis in narrow frequency sub-bands.

RESULTS

According to EEG data, the functional state of the cerebral cortex of patients in group 1 at the stage of remission was approaching normal. The EEG of group 2 and group 3 differed from the EEG of group 1 by significantly lower values of EEG spectral power in the alpha3 sub-band (11—13 Hz) in the occipital leads and a significantly increased content of theta1 (4—6 Hz) activity in the central-parietal areas. Such EEG frequency structure of patients in groups 2 and 3 reflects a reduced functional state of associative areas, and may also indicate dysfunction of the frontal parts of the cerebral cortex. These EEG features of patients in groups 2 and 3 are consistent with a significantly greater severity of their positive and negative symptoms on SAPS and SANS compared to group 1.

CONCLUSION

In patients with depression at the stage of remission who have symptoms of an ultra-high risk of developing psychosis and in those who have suffered a psychotic episode, a reduced functional state of the associative and frontal areas of the cerebral cortex is noted, which may underlie the characteristics of their clinical condition.