Clinical and electroencephalographic (EEG) analysis ofladasten action in anxiety-asthenic patients with respect to their EEG-defined individual typological characteristics was carried out. Primary psychopathologic disorders and ladasten effects were assessed by objective classification methods (factor and cluster analyses), and individual EEG types characterized by marked or reduced alpha rhythm were determined. No significant correlations between baseline EEG results and the initial mental condition indices were found. Significant differences ofladasten action in patients with different EEG types were found. It was established that, in patients with marked alpha rhythm corresponding to asthenic personal traits, ladasten exhibits predominantly a psychostimulant action assessed by clinical rating scales, which is accompanied by high frequencies of alpha rhythm increase and beta 1 and beta 2 rhythms decrease. In patients with reduced alpha rhythm and the EEG type corresponding to asthenic personal traits, ladasten action was characterized by an increase of alpha-rhythm low frequencies and the opposite reaction of beta 1 and beta 2 rhythms, whose are typical for the EEG pattern of anxiolytic effect. These results may indicate that the effect of ladasten depends on the initial brain activity level, which varies in patients with different individual typological traits.