Neuron 59, 207–213 (2008) doi:10.1016/j.neuron.2008.06.019

Levels of neurosteroids derived from the hormone progesterone fluctuate during the menstrual cycle and soar during pregnancy. But abnormal levels are associated with disorders such as premenstrual dysphoric syndrome and post-partum depression.

Neurosteroids act through the GABAA receptor to modulate excitability of brain cells. Using genetically modified mice that lack the delta subunit of the GABAA receptor, Istvan Mody and Jamie Maguire at the University of California, Los Angeles, found that females showed depressive and anxious behaviours after giving birth, and did not care properly for their pups.

Failure to regulate GABAA receptors as neurosteroid levels plummet after giving birth may similarly underlie human post-partum depression.