By Sophia Glezos Voit

Those tearful, overwhelmed, wiped-out feelings that can develop after childbirth are normal, said Dr. Catherine Roca, NIMH scientist who spoke to NIH employees at a recent session of the Seminar Café, held at the Neuroscience Center, on post-partum mood disorders. The "baby blues" affect about 50-80 percent of new mothers, and generally resolve within a week.

But symptoms don't abate quite so quickly for about 10 percent of new mothers, according to Roca, formerly an intramural researcher who now heads the institute's extramural Women's Research Program. Unless treated, depression's sad moods, inability to feel pleasure, appetite changes, insomnia, thoughts of death, and other symptoms can persist for months on end, and affect every area of functioning, including caring or even feeling affection for the baby.

In addition to clinical depression, some new mothers also develop psychosis, e.g., auditory hallucinations, mania and delusions, Roca said, though only 1 in 1,000 women and mostly those with a family history of bipolar or schizoaffective disorder, are affected.

NIMH's Dr. Catherine Roca discussed post-partum depression in a talk for employees.

What causes post-partum mood disorders? "For the most part, no one really knows what's going on at the biological level," Roca said, though known risk factors include low social support, a personal or family history of mood disorders, prenatal depression, child-care stressors and marital problems. The areas of current research, though, include reproductive hormones and genetics.

Following delivery, all women experience a sudden drop in estrogen and progesterone levels — hormones that are also potent regulators of certain mood-affecting brain chemicals such as serotonin. But, clearly, not all new mothers get depressed.

Comparing the effect of artificially increasing and then suddenly withdrawing these hormones in mothers with and without a history of post-partum depression, NIMH researchers have found that moms who never had post-partum depression did not experience mood symptoms when the hormones were stopped, but the ones who've had PPD in the past did feel depressed.

"So, probably in a manner very similar to what you find in premenstrual dysphoric disorder," Roca said, "there's probably a sensitivity to developing mood-state changes relative to changes in hormone levels in these women. But, the reasons for this sensitivity aren't currently known."

A cause of post-partum mood problems that researchers do know about, Roca said, is the development of thyroid disturbance following birth, since autoimmune thyroiditis, which occurs in about 8 percent of new mothers, results in nearly identical symptoms. "This is something that should always be checked when someone is displaying depressive symptoms," Roca advised, especially because treatments such as thyroid hormone replacement are effective.

At present, treatments for post-partum depression are similar to those for major depression in general, though NIMH is also studying the use of estrogen replacement. But, said Roca, "the use of antidepressants has been relatively understudied in post-partum depression."

There is a need for drug studies in this area, Roca said, since there has only been one randomized controlled trial of a medication versus placebo versus interpersonal therapy. It found fluoxetine (or Prozac) was superior to placebo but comparable to therapy.

"This is important," she said, "because not everybody responds to psychotherapy, and it can be very difficult for women with this disorder to come in for weekly therapy sessions. There are also a number of cases where people really have severe symptoms and need to have medication management."

But of most concern to depressed new mothers is medication excretion in breast milk. "It's one of the reasons that many women will not get into treatment," Roca said. "And there are relatively few studies on this. Of the ones that have been done, SSRI's [e.g., fluoxetine, sertraline, etc.] have been shown to be generally without adverse effects. But they're mostly case studies and the long-term effects in infants are not known."

Yet, Roca noted, untreated depression itself is known to have effects on long-term development in children, at least until age 5. And in animal studies, offspring show long-term effects in their response to stress if they have been raised by a depressed mother. So, Roca stressed, there are potential consequences for the baby whose mom has untreated depression.

There are no approaches yet for the prevention of post-partum mood disorders, Roca said. For this reason, pre-pregnancy planning with a professional who specializes in the treatment of related disorders is important for women who have already had one episode of PPD, since they are at increased risk of having another.

Prospective mothers with a family history of post-partum psychosis may want to make pre-pregnancy planning a high priority, since they face a 70-75 percent higher risk of developing the illness themselves. The exact genetic vulnerabilities are not known, Roca said, but one recent report has found an association with one of the serotonin transport polymorphisms and post-partum psychosis.

"This is not to say women who have been depressed or whose mothers or sisters developed the disorder should not get pregnant," Roca said.

Resources for new mothers and families facing this diagnosis include: Depression After Delivery, (800) 944-4773; Depression and Bipolar Support Alliance, (800) 826-3632; Family Mental Health Association, (800) PPD-MOMS.