Clinicians since Hippocrates have noted an association between the postpartum
period and mood disturbances.1 This linkage
entered official psychiatric nomenclature in 1994, when the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition
defined major depression with postpartum onset as episodes of depression beginning
within 4 weeks of giving birth.2 This time
period corresponds to the rapid hormonal changes posited to contribute to
vulnerability to depression. However, because psychosocial factors also play
a major role in triggering postpartum depression, most researchers use a working
definition of the postpartum period as lasting up to 6 months after delivery.