Study: Some stressed moms get hostile, some seem insensitive

Parenting is often stressful, but new research shows why chronic stress impairs the way mothers react to children.

Researchers measured the physiological stress responses of 153 mothers (about half low-income, half middle- to upper-income) and found that those facing ongoing stress, such as depression or poverty, were either more harsh and hostile or more insensitive and neglectful toward their toddlers.

The study, published online in the journal Development and Psychopathology, shows chronic stress disrupts the body's natural stress response, which is to react and then recover, says lead author Melissa Sturge-Apple, assistant professor of psychology at the University of Rochester in New York.

Researchers used a wireless electrocardiograph monitor to analyze changes in mothers' heart rhythms as children were placed in a mildly distressing situation and then observed the pairs during play. They also asked questions about symptoms of depression.

Mothers with more depressive symptoms showed heart rate patterns that began higher and rose during their toddlers' distress. After being reunited, moms' heart rates remained elevated and their actions were more hostile, such as making derogatory comments in an angry tone. Mothers in poverty had heart rates that began lower and rose little during their child's distress. During play, they were more likely to ignore their kids and not respond when toddlers wanted attention.

"Mothers with higher levels of depressive symptoms were more reactive; the ones in poverty were more likely to be less reactive," Sturge-Apple says.

The body handles stress either by heightening reactions or shutting down; what's counterintuitive, she says, is that those more likely to be depressed aren't withdrawn but rather hostile and angry.

Those results confirm what sociologist Robin Simon of Wake Forest University in Winston-Salem, N.C., found in a 2010 study published in the journal Social Forces. She sees a clear link between depression and anger and hostility.

"They're already in a funk, so they're going to be more reactive. At the same time, greater reactivity to parental stress may be why they're depressed," she says.

Economist Julieta Lugo-Gil, a senior researcher at Mathematica Policy Research Inc. in Princeton, N.J., also has studied low-income mothers. Her analysis of 2,089 mothers with kids 14 months to 3 years was published in 2008 in the journal Child Development.

It found that factors such as the mother's education and literacy level and whether she lived with the child's father help her be more sensitive and supportive when a child is upset.

"If you have less resources, then the quality of the interaction is not as good," she says