Publisher Summary Rapid advances have been made in understanding the neurochemical mechanisms of benzodiazepines (BZs) and similar compounds responsible for their therapeutic actions. The “GABA hypothesis” relating to the actions of BZs in the brain continues to gain support. The psychopharmacological effects of the BZs may be due, at least in part, to their ability to potentiate and prolong the synaptic actions of the inhibitory amino acid GABA. The existence of a novel bicuculline-insensitive GABA receptor, which is different from the conventional postsynaptic inhibitory GABA receptor, has been reported. Systematic reviews of BZs in clinical use have recently appeared as having clinical studies on the treatment of anxiety states with Alprazolam, Camazepam, Clobazam, and other medicines. Intravenously administered Clonazepam was shown to be effective and devoid of serious side effects in the treatment.