The spectral-coherence analysis of phenazepam single-dose action in patients with anxiety disorder was performed. Significant changes in coherence parameters indicating the generalized character of reorganizations of interzonal connections with the involvement of delta, alpha, theta and beta-1 to beta-3 rhythms, including both their strengthening and weakening, were revealed. Correlations between the character of reorganizations of interzonal relations and subjective assessments of the drug effect were observed: activating and antianxiety drug effects were correlated with tolerability and the wish to continue treatment with the drug. Results suggest that drug effect on EEG spectra is more informative when subjective assessments are taken into account.