Objective:
The study of the features of the higher mental functions of the brain in patients suffering from addiction to psychoactive substances is very important for narcology. It is necessary not only to uncover the mechanisms of addiction, a complete understanding of the neurophysiological processes that determine the nature of the development and severity of the disease, but also to solve practical problems related to the development of treatment methods and the implementation of preventive measures.

Method:
In the study of patients, a specially designed map was used containing information on the hereditary and demographic characteristics, on the course of the disease, as well as on the socio-cultural status of patients. To determine the functional state of cortical activity in the process of perception of unconscious signals, a special technique was used. The obtained results were subjected to dispersive analysis and the significance of differences was calculated according to Student’s t-criterion.

Results:
An analysis of premorbid personality traits made it possible to establish the prevalence of instability, pathological conformity, and hysteroidal features in patients. It should be noted that a large percentage of the surveyed had a hereditary burden of alcoholism, mainly in the line of the father. Curiosity, passive submission, imitation of friends were among the motives of the first drug use. All patients in the process of addiction formed the following features: increased excitability, increasing effective disorders (depression, dysphoria), aggravated by exacerbation of craving for the drug, a decline in morals and ethics (egoism, deceit, indifference to one’s fate, hedonism, loss of sense of duty), disorders of the emotional-volitional sphere (emotional instability, hypersensitivity, vulnerability).

Conclusion:
The analysis of the duration of latent periods and magnitude of the amplitudes of the late positive R3OO wave in patients with heroin addiction revealed clear differences between the data obtained upon presentation of an unconscious neutral and motivationally significant word. Patients who use psychoactive substances, using the method of recording induced potentials of the brain, which is a sensitive indicator of the activity of brain structures in relation to the substance used, revealed a clear diffuse activation of the cerebral cortex in response to an unconscious verbal stimulus related to the motivation prevailing in patients, in particular to “heroin”. Such activation, as well as the difficult dying out of the developed reactions to an unconscious stimulus, indicate certain neurophysiological foundations of the mechanism underlying the changes in the motivational sphere and the stability of the pathological craving for the psychoactive substance.