The 74 persons, including the 39 persons with mental and behavioral disorders due to psychoactive substance use (PAS) and the 35 persons with subclinical forms of substance use, are examined. The olfactory EEG patterns, differing in narcological patients depending on the range of PAS used, are revealed. EEG markers of olfactory response to isopropanol, thymol and androstenone in combination with emotional evaluation, having hemispheric features, can be diagnostic and differential predictive factors for assessment of predisposition to mental and behavioral disorders due to PAS use.