Electrophysiological evidence for an inverse benzodiazepine receptor agonist in panic disorder

Inverse agonists of the GABA(A) receptor clearly decrease the amplitudes of the spontaneous EEG in the beta-frequency range. Therefore, we tested the hypothesis that panic patients exhibit a reduction of the EEG's spectral po wer in the beta-frequency band. Ten unmedicated patients with panic disorde r and agoraphobia according to DSM-III-R criteria and 10 matched controls w ere investigated under baseline conditions, after hyperventilation and 30 m in after hyperventilation. EEG recordings from the position P-z and C-z wer e performed under eyes closed conditions. At baseline conditions the patien ts suffering from panic disorder depicted a reduced beta-power reaching sta tistically significance for lead position P-z. Immediately after hyperventi lation for both channels we observed a decreased beta-power. After hyperven tilation we observed the same situation as under baseline conditions. Taken together, our results point to the view that in panic disorder an endogeno us inverse agonist of the GABA(A)-benzodiazepine receptor could be hypothes ized. (C) 1999 Elsevier Science Ltd. All rights reserved.