Non-psychotic major depression is estimated to occur in approximately 10 percent of mothers in the early weeks following delivery. Many new mothers appear to be vulnerable to depression in the first three months following pregnancy. Because this illness may result in disturbances of the cognitive and emotional development of the child, Cooper and Murray undertook a major review of postpartum depression.

Little biological basis has been identified for postpartum depression. The incidence may be increased in certain risk groups, including women with a history of depressive disorder, complications during delivery and certain other obstetric factors. Psychologic stressors consistently associated with postpartum depression include unemployment, marital conflict and lack of personal support from family and friends. The strongest association appears to be with previous depression. Attempts to develop predictive models for postpartum depression have achieved only modest sensitivity and specificity. In contrast, the condition may be reliably detected by self-reported scales such as the Edinburgh postnatal depression scale, which has been used in large-scale screening.

Postpartum depression may be initially overlooked by health care professionals but is usually a straightforward diagnosis. Several treatment strategies have been advocated, but few scientific studies have been conducted. No systematic evidence to validate the use of progesterone therapy has been found. One trial revealed a significant improvement in mood in patients who were treated with estrogen compared with placebo. Both fluoxetine and psychologic counseling were also found to be superior to placebo in a controlled trial, but more than one half of the patients declined to take antidepressant medication. Psychologic support has been found to be more effective than routine care in at least three published trials. Although few studies have examined the ways treatment affects the mother-infant relationship, evidence has shown that treatment significantly improves both the mother's mood and the quality of the mother-infant relationship. Children of depressed mothers have been shown to perform more poorly on cognitive tests at 18 months of age than did children of mothers who were not depressed.

The authors conclude that early detection of postpartum depression and early treatment by primary care physicians is important to lessen any disturbance in the relationship of the mother and child. Episodes of postpartum depression usually remit spontaneously two to six months after onset, but residual depressive symptoms may persist beyond one year. This effect was more marked in boys and, in other studies, persisted until five years of age.