I wonder about the use of estrogen for postpartum depression on a total 'nother level.  When I started dealing with depression in my late 40's that was finally decided was perimenopausally, hormonally caused, half the docs said "oh, just take hormones" (as cavalierly as that).  Fortunately the other half the docs I dealt with on a daily basis said, "oh, often hormones make the depression worse.  Take something for the depression."

Several experiments with meds find me finally, and happily, on Paxil -- which helps whether the depression rises from the wildly fluctuating hormones of menopause, and the still monthly fluctuating hormones causing PMS.