Materials and Methods. There has been given a brief historical background of the study of the role of endogenous opioid system (EOS) in regulation of body functions. A comparable analysis of the heart rate variability dynamics was carried out in drug-addicts with reduction of EOS receptor apparatus and healthy volunteers in the context of cognitive loads of different levels. 135 individuals were examined: 64 patients of the narcologic clinic with addiction to opiates composed an experimental group, and 71 healthy students were included into the control group. A measured cognitive load was formed using hardware-software complex Handtracking (Russia). Long-term continuous monitoring of heart rate was carried on by means of mobile telemetry.
Results. The psychophysiological markers of EOS activity during interactive communication with information images were determined on the basis of parameters of the heart rate variability and threshold characteristics of cognitive functions. It was established, that control and experimental samples were statistically significantly different by the frequency-domain indices of the heart rate variability in the stationary context of rest and in solving cognitive tasks (p<0.05), i.e. reduction of the mode of the autonomic regulation of heart rate and lack of adaptative alterations in the structure of the heart rate in case of changing the external information context, were characteristic of the examined drugaddicts. The most informative functional tests, the data of which make it possible to identify most effectively the condition of EOS and to develop noninvasive methods of diagnosing narcotization and addiction, were selected from the suggested contexts. Methods of collecting physiological data, minimizing the risks of cognitive context distortion, implying involvement of resources of the cognitive system in the process of measuring or interaction with an expert, were used for the first time.