Among 88 reproductions to women with a history of nonorganic psychosis, 25 postpartum episodes (PPPs) occurring during the total 6-month period following the current delivery were not systematically related to the woman's demographic characteristics, to her psychiatric history characteristics surrounding onset of the previous disorder or to a history of PPPs following previous reproductions. PPPs were highly significantly related to greater length of previous psychiatric hospitalization and to active mental disturbance just prior to this pregnancy, and this was true both for PPPs developing within 3 weeks of delivery and for those developing later. Considerable differences were found in the demographic characteristics that were related to development of PPPs within these Early vs. Later Onset cases, suggesting these to represent different disorders not only diagnostically but also demographically. In several diagnostic categories, selected demographic or psychiatric history characteristics identified subgroups with PPP rates as high as 75%.