Dr. Elizabeth O’Connor and colleagues studies the importance of depression screening in women during and after their pregnancy. They published their research in the prestigious Journal of the American Medical Association (JAMA). A full text version is available for free through JAMA.
Dr. O’Connor, why do you find this topic important?
Depression is common for women during the pregnant and postpartum period and very difficult for them and their families.
What was the goal of your study?
Our goal was to examine whether screening and treating pregnant and postpartum women for depression in primary care settings reduces depression in these women. We also looked at whether there are harms associated with these services. Finally, we asked whether screening tools commonly used to help doctors identify women who are depressed are accurate in figuring out who is depressed.
What did you do to study the topic?
We searched for already existing studies that would help us answer these questions, covering several different types of studies.
- Screening studies. We looked for studies that compared a group of women who were screened for depression in a primary care setting (including obstetrics-gynecology) with a group that was not screened–or at least, where the primary care clinicians for the women in the control group never got the results of the screening test. A positive screening test was followed up with a more thorough assessment of the woman and an offer of treatment, if it was called for. In the control groups, the primary care clinicians didn’t know about the women’s depression and it was up to them to use their normal method to figure out who needed treatment and help them get access to the services that were normally available in their healthcare system.
- Treatment studies. We also looked for studies among women were screened for depression and then randomized to either treatment through the study or referrals to typical resources available in their community or healthcare system. The study-provided treatment usually involved a carefully controlled protocol and specially trained treatment providers, and women in the control groups sometimes had the promise of getting the study-designed treatment protocol at a later time.
- Diagnostic accuracy studies. We looked at studies that compared the results of a couple commonly-used depression screening instruments with the results of a more extensive diagnostic interview. These studies then reported on how many of the women who really were depressed according to official diagnostic criteria had a positive screening test, and other related statistics.
- Harms of antidepressants. Finally, we also looked for studies that examined whether using antidepressants could be harmful to pregnant or postpartum women.
Could you describe your findings?
We concluded that screening pregnant and postpartum women for depression may reduce depressive symptoms in women with depression. And, screening a large group of women for depression is likely to reduce the percent of women meeting criteria for depression, presumably because those who screen positive are then sent on to get appropriate assessment and treatment. Specifically, six studies (that included 11,869 women) showed 18% to 59% reductions in depression after participation in programs involving depression screening, compared to usual care. The ten treatment studies we found that used cognitive behavioral therapy or other similar treatment approaches (which included 1,638 women) supported this conclusion: when screening was used to find women who needed treatment for depression, cognitive behavioral therapy was helpful. Other modes of treatment didn’t have a lot of evidence and we couldn’t determine whether or not they were helpful. We also found that a widely-used screen instrument (the Edinburgh Postnatal Depression Scale), which can be used in primary care settings, did a reasonably good job of identifying women who are depressed.
Most of the evidence for screening and treatment was in postpartum women, but the evidence for pregnant women was very consistent with the evidence for postpartum women. One difference between pregnant and postpartum women, though, was that we found evidence to suggest that using some antidepressants during pregnancy may increase the risk of some potentially serious harms, such as preeclampsia, miscarriage, preterm birth, seizures, pulmonary hypertension, congenital malformations, and even possibly perinatal death.
Do you see limitations to these important findings?
There are some important limitations to our conclusions. First, there were only six screening studies, which is not a very large body of evidence. And, these studies used a wide range of strategies and most included treatment along with screening, so we couldn’t clearly separate the value of screening from the value of the combination package of screening plus consistent, protocol-based treatment. Also, studies reported a wide variety of outcomes, so even though we say that the risk of depression was reduced, some studies only reported that women scored below a certain level of symptoms, not that they were truly depression-free. Finally, when relying on published studies rather than conducting your own screening and treatment studies, it is possible to misunderstand a study’s methods or results, or propagate errors in those studies that we couldn’t know about. However, on balance, we found it encouraging that the separate bodies of evidence were consistent with each other and suggested that depression screening is likely to reduce depression.