Antidepressants are divided into several groups such as monoamine oxidase inhibitors, serotonin reuptake inhibitors, noradrenaline reuptake inhibitors and alpha-adrenoceptor antagonists. Antidepressants show, however, a common clinical profile: their clinical actions occur after a chronic treatment. It is, therefore, suggested that antidepressants have a common pharmacological profile. We reviewed possible involvement of gamma-aminobutyric acid (GABA)B receptors in action of antidepressants. Our data in combination with previous ones from other laboratories suggest that antidepressants suppress the activity of presynaptic 5-hydroxytryptamine3 receptors on GABA neurons, resulting in the reduction of GABA release. It is likely that the decrease in GABA release attenuates GABAB receptor-mediated neurotransmission, thereby upregulating GABAB receptors.