Seventy to 80 percent of new mothers experience mild "maternity blues" that begin on or about the third day following delivery.

Symptoms include tearfulness, sleeplessness, tension, anxiety, frequent mood changes, and anger. They come and go for a day to a week, and then disappear.

Some 10 to 20 percent of new mothers, however, move into a full clinical depression, lasting two to eight weeks, but sometimes as long as a year.

In addition to the usual symptoms of major depression, women suffering...