To expose the very first signs of depression, Stanford psychologist Ian Gotlib, PhD, began studying teenagers who had mothers with depression. But he soon realized he needed to go back even earlier in a child's life.
"In a sense, we were already late," Gotlib said in a recent Stanford News article about his decadeslong pursuit of the roots of depression. "At 10 years old, these children already have what some people would call early signs of depression. They were already exhibiting abnormalities."
So his team adjusted. Along with teenagers, they turned to pregnant women and infants to learn more about precursors to the mood disorder.
Gotlib and his lab members, as well as other researchers, have homed in on the importance of cortisol, a hormone released in response to physical or mental stress. To examine a baby's exposure to stress in utero, his team is testing samples of expectant mothers' hair at various stages of their pregnancies.
The article explains:
Gotlib and others have shown that early life stress can alter cortisol levels, which in turn can reduce the size of the hippocampus, part of the brain that plays an important role in learning and memory. A smaller hippocampus has been linked to greater risk of depression, anxiety, suicidal behavior and other mental disorders in later life. A recent study in Developmental Science, led by Kathryn Humphreys, [PhD] an assistant professor at Vanderbilt University and a former postdoctoral fellow in Gotlib’s lab, found that hippocampal growth is especially sensitive to stress during the first five years of a child’s life.
The work raises a critical question: If the researchers discover troublesome signs in children, is there any way to change course? Can loving caregiving make a difference?
One study in the lab is designed to help clarify that by recording all sounds a baby hears. “We can get basic measures of how many adult words are spoken near the infant and how many times the infant vocalized in response,” graduate student Lucy King explains in the article. “We want to know, what are the relative effects of the pre-birth versus postnatal environments on infant brain development? … And can enrichment postnatally remediate the effects of a negative prenatal environment?”
Helping to prevent depression in the first place is the goal uniting the lab's array of investigations.
“If we can identify what that risk profile looks like, then we can develop prevention programs that target those mechanisms that we think are contributing to the development of depression and suicidal behaviors,” Gotlib said.
Photo by Misha Bruk
