Three groups totalling 84 women were compared: postpartum depressed (PPD) women, postpartum nondepressed women, and a control group of matched normals. Participants filled out the Affects Balance Scale (ABS) and the Beck Depression Inventory. Raters scored participants' narratives, elicited at different levels of arousal, with the Epigenetic Assessment Rating Scale (EARS), along dimensions of affect tolerance (AT), affect expression (AE), and personal agency. PPD responses were characterized by a global regression to earlier levels of personality organization. AT and AE were areas of vulnerability for all postpartum women under conditions of stress or high arousal. There was a strong relationship between level of organization on AT and the extent to which positive and negative affects were polarized on the ABS, supporting both the hierarchical structure of the EARS and an understanding of affective development as a growing ability to tolerate, differentiate, and express emotions, with increased modulation at higher levels.