Depression in women has about a 10% incidence, according to the CDC. That means that 1 in 10 women will experience depression at some point in their lives. For many women, it happens when they become a parent, and while that isn't unexpected, new research shows that depression in a mom can have an adverse effect on the IQ of their children.
Researchers from the University of California San Diego School of Medicine looked at depression in moms and compared it to the IQ levels of children. Their findings, published in the journal Child Development suggest that depression in a mother can impact IQ in her children well into their teen years.
The data for the study was collected from more than 900 healthy children in Santiago, Chile. The study participants were followed from infancy through their 16th birthday, with surveys and assessments at five-year intervals. The team looked at affection and response time of mothers when they were interacting with their children, as well as educational toys and books that the mothers in the study used with their children. The children also underwent standard IQ tests that measured verbal cognitive abilities in these check-ins, and the mothers were evaluated for symptoms of depression.
Patricia East, Ph.D. was the lead author of the study. She is a research scientist with the Department of Pediatrics at UC San Diego School of Medicine. She explained, "We found that mothers who were highly depressed didn't invest emotionally or in providing learning materials to support their child, such as toys and books, as much as mothers who were not depressed. This, in turn, impacted the child's IQ at ages 1, 5, 10 and 16. The consistency and longevity of these results speak to the enduring effect that depression has on a mother's parenting and her child's development."
So how did the numbers break down? The verbal IQ scores for the children were on a scale from 1 to 19. In the assessments made when the children were five years old, the average IQ score was 7.64. Children whose mothers were found to be severely depressed had a somewhat lower average score of 7.30. Children who had mothers who were not depressed showed slightly higher than average scores, coming in at an average of 7.78. While neither of these ends of the spectrum is that far from average, the difference was noted by the investigators.
The incidence of depression among the mothers was also significant. The team found that at least half of the moms in the study reported depression symptoms based on their answers to standard questions like, "Are you sad?" and "Do you find yourself crying frequently?" Part of that could be due to the environment from which the mothers were chosen. Many had only about nine years of formal education, did not have jobs outside the home and lived with extended families in homes that were small and often crowded. All of these factors are also risk factors for depression in mothers. The researchers also found that while post-partum depression is not unusual regardless of housing or education status if depression in a mother persisted past the child's first birthday, the likelihood that it would linger and become chronic was increased.
The study highlights the need for better care for women after they have children. Primary care doctors, midwives, and obstetricians need to be aware of the signs of persistent "baby blues" so treatment can begin and any negative impact on IQ can be mitigated. Take a look at the video to learn more about the signs of depression in mothers.