Emapunil acts as a selective agonist at the peripheral benzodiazepine receptor (TSPO). At the cellular level, the selective TSPO ligand XBD173 potentiated the amplitude and duration of GABA-mediated inhibitory postsynaptic currents in mouse medial prefrontal cortical neurons, which was prevented by finasteride. In animal and human trials, XBD173 produced rapid anxiolytic and anti-panic effects probably via newly synthesized neurosteroids, without producing sedation or withdrawal symptoms, and may represent a promising target for the development of fast-acting anxiolytics with a more favourable side-effect profile than benzodiazepines.