Neuronal GABA(A)/benzodiazepine and monoamine receptors participate in anxiety. Diazepam binding inhibitor (DBI), an endogenous anxiogenic neuropeptide, significantly increases in brains only after treatment with psychological stress, and this increase is completely abolished by benzodiazepines. Therefore, it is through that DBI may be involved in anxiogenesis produced by psychological stress. Furthermore, increases in cerebral DBI are observed in patients with several disorders accompanying anxiety and fear, which suggest that cerebral DBI may be an essential factor for anxiogenesis, and that it may be, at least in part, a biological index to evalulate anxiety.