Postpartum Psychosis and Bipolar Disorder: Review of Neurobiology and Expert Consensus Statement on Classification.

Postpartum psychosis (PP) is an acute and severe psychiatric illness with onset within weeks after delivery and a high risk of suicide and infanticide. Most women with PP experience severe mood symptoms, including mania, mixed episodes, or depression with psychotic features. Impaired cognition, irritability, and agitation are also common. The specific timing of PP strongly suggests a biological basis, because the postpartum time period is characterized by profound endocrine, immune, neuroanatomical, and physiological changes in the brain. Genetic studies show a unique risk architecture, partly shared with bipolar disorder. PP stands out as one of the most distinct clinical phenotypes in psychiatry due to its characteristic rapid onset, severity, phenomenology, treatment response, and prognosis. Despite this, as of August 2025, PP does not have a distinct diagnostic classification in the DSM. This expert consensus panel, in close collaboration with patient organizations and key interested partners, recommends classifying PP as a distinct category within DSM-5 and ICD-11. We recommend classification within the bipolar disorders chapter of the DSM because 1) most women with PP have prominent affective symptoms; 2) treatment response to lithium and electroconvulsive therapy is excellent; 3) in half of the cases, first-onset PP is also the first onset of bipolar disorder; 4) pregnant women with bipolar disorder are at very high risk of PP; and 5) the genetic risk architecture for PP is distinct but overlapping with bipolar disorder. This consensus statement summarizes scientific evidence that PP is a distinct mental illness within the bipolar spectrum; correct classification will improve detection and treatment.