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 power in the beta-frequency band. Ten unmedicated patients with panic disorder and agoraphobia according to DSM-III-R criteria and 10 matched controls were investigated under baseline conditions, after hyperventilation and 30 min after hyperventilation. EEG recordings from the position P-z and C-z were performed under eyes closed conditions. At baseline conditions the patients suffering from panic disorder depicted a reduced beta-power reaching statistically significance for lead position P-z. Immediately after hyperventilation for both channels we observed a decreased beta-power. After hyperventilation we observed the same situation as under baseline conditions. Taken together, our results point to the view that in panic disorder an endogenous inverse agonist of the GABA(A)-benzodiazepine receptor could be hypothesized. (C) 1999 Elsevier Science Ltd. All rights reserved.