Using visual evoked potential test for revealing lies about drug intake

Aim. To study the features of visual evoked potential in potential military recruits for revealing lies about drug intake. Methods. 114 subjects were examined. Electroencephalography, urine test for drug traces, polygraph test were performed to reveal the risk factors for drug intake. All subjects were allocated to three groups. First group included potential military recruits who were not taking drugs (34 subjects, 29.8%). Second group included potential military recruits who tried psychoactive drugs for 1-5 times, but in whom no risk factors were revealed on polygraph test (21 subjects, 18.4%). Third group included potential military recruits who tried psychoactive drugs for 5-15 times, and in whom risk factors were revealed on polygraph test (31 subjects, 27.2%). Fourth group included potential military recruits who tried psychoactive drugs for 5-15 times, and had marked risk factors according to polygraph test (28 subjects, 24.6%). Psychoactive substance traces were revealed by urine test in 8 subjects. Graphical representations of different situations associated with drugs intake were used as a stimulus at visual evoked potential test. Results. Changes in visual evoked potential test as a response to a slideshow depicting situations associated with drugs intake might be seen in potential drug addicts long before stereotyping the drug abuse. The most informative parameters of evoked brain activity are amplitudes of 250-550 ms, where a statistically significant difference between the amplitudes of visual evoked potentials in individuals with and without history of drug abuse was revealed. The amplitude of P300 wave in individuals who do not use drugs was significantly higher compared to drug abusers. Software allowing to predict the higher chance of possible drug abuse was developed at the basis of the research. Conclusion. The method of visual evoked potentials showed high predictive value for the diagnosis of drug abuse among possible military recruits; obtained results might be used in the professional selection of persons in hazardous occupations.