In 2004, Dr. Tim Oberlander’s attention was drawn to a paper in Science reporting a study by colleagues in New York.
The researchers reported that mice with early life exposure to a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs) were much more anxious in adolescence than mice who had not been exposed to SSRIs.
Dr. Oberlander and colleagues had been studying the mental health of pregnant mothers and their children following prenatal exposure to SSRIs since 1996 and had noted that mothers who’d been treated with an SSRI during pregnancy reported their three-year-old kids were more anxious than non-exposed children.
“Given that SSRIs are supposed to treat anxiety, this was a somewhat odd finding,” says Dr. Oberlander.
Even more surprising was that as these children reached early school age they continued to be more anxious than non-exposed children. These results led Dr. Oberlander and postdoctoral fellow Dr. Sarah Hutchison to study outcomes in the same group of women and children at around age 12.
In a recent paper published in BJPsych Open, they reported that a mother’s depressed mood during the third trimester — not prenatal SSRI exposure alone — had a lasting impact and was associated with higher levels of childhood anxiety from three to 12 years of age.
Participants were recruited during their second trimester as part of Dr. Oberlander’s larger longitudinal cohort study. The researchers collected mothers’ reports of anxiety and depressive symptoms in their children at three, six and 12 years. Dr. Oberlander and the research team considered how these child symptoms changed over time and studied relationships between the child’s prenatal exposure to SSRIs and the mother’s mood during the third trimester, and three, six and 12 years postpartum.
While some might presume a mother with depression could have a more negative assessment of their child’s symptoms, Dr. Hutchison says their previous paper showed that maternal reporting — even from a mother with depression — is accurate.
“In a research setting like this, it’s really powerful to have the mother’s view of their child,” agrees Dr. Oberlander.
Antidepressant exposure isn’t the problem
Over the past two decades of research, Dr. Oberlander has come to see the prenatal SSRI exposure story in a much more complex and nuanced way. He believes some women benefit from SSRI treatment during pregnancy and, by extension, their children benefit as well.
“Others treated with an SSRI remain symptomatic during pregnancy and many years after. Their depressed mood during pregnancy turned out to be by far the strongest predictor of behavior across childhood,” says Dr. Oberlander.
These findings may suggest that for some mothers who were treated with an SSRI during pregnancy, the antidepressant may have been ineffective and the mother’s depressed mood emerged as the strongest predictor of their child’s development. Beyond a failure of the medication to effectively treat mood disturbances, risk factors may also include shared genetic factors that predispose both the mother and her children to a mood disturbance and everyday environmental factors that accompany a mother’s depression and affect her child’s behavior long after birth.
It’s clear from Dr. Oberlander’s work that there are therapeutic benefits of SSRIs, yet identifying who can benefit, and why, remains an active area of his research.
“Mother’s mood matters,” says Dr. Hutchison. “We need to figure out how to best support women and their families.”
One of their key findings is that both the mother’s prenatal and current mood was more predictive of the child’s mood across childhood.
“While it’s critical to assess maternal mood during pregnancy and the early post-partum period, we really should be paying attention to it for a longer range of time,” says Dr. Hutchison.
“Anyone providing child health care should be asking about a mother’s mood at every child health encounter as a critical way to promote child development and using this opportunity for timely interventions,” Dr. Oberlander adds. “We should focus on effectively supporting a mother’s mood as a way to promote healthy development over the child’s early years, regardless of whether the child had prenatal SSRI exposure.
“Identifying mothers who are depressed during pregnancy and can benefit from treatment, whether it’s from an SSRI or non-pharmacological options, remains an urgent task as we seek ways to optimize their children’s development and promote well-being long after infancy,” he adds.
Dr. Hutchison has been studying early cognitive development and mood in these children since they were 12. Her research in this area continues.
Of the 191 births that Dr. Oberlander’s team started following nearly two decades ago, more than 110 families continue to participate in his longitudinal study at 15 to 18 years of age. The researchers are now studying the everyday lives of mothers and their children using Dr. Oberlander’s Living Lab at Home platform. They’re about halfway through examining patterns of social interaction and feelings of sadness and anxiety using a custom-designed smartphone app, accelerometers to measure daily physical activity and biomarkers found in saliva.