The clinical features of postpartum depression and depression occurring outside of the postpartum period have rarely been compared. The 16-item Quick Inventory of Depressive Symptomatology-Self-Report (QIDS-SR(16)) provides a means to assess core depressive symptoms. Item response theory and classical test theory analyses were conducted to examine differences between postpartum (n=95) and nonpostpartum (n=50) women using the QIDS-SR(16). The two groups of females were matched on the basis of age. All met DSM-IV criteria for nonpsychotic major depressive disorder. Low energy level and restlessness/agitation were major characteristics of depression in both groups. The nonpostpartum group reported more sad mood, more suicidal ideation, and more reduced interest. In contrast, for postpartum depression sad mood was less prominent, while psychomotor symptoms (restlessness/agitation) and impaired concentration/decision-making were most prominent. These symptomatic differences between postpartum and other depressives suggest the need to include agitation/restlessness and impaired concentration/decision-making among screening questions for postpartum depression.