Mom's depression linked to infant stress

TORONTO, Sept. 19 (UPI) -- A Canadian study suggested an association between a history of depression in the mothers and increased stress reactivity of their infants.

The study, published in Biological Psychiatry, also linked increased stress reactivity to a particular style of mothering known as "maternal overcontrol."

Researchers found an increase in the stress hormone -- cortisol -- following a mild stressor in infants whose mothers have a history of depression and a pattern of intrusive and overstimulating behavior toward their infant known as "maternal overcontrol." These infants also had lower pre-stress cortisol levels. In addition, there was a correlation in the cortisol levels between mothers and their infants.

These findings add "to our small but growing body of knowledge on neurobiological differences in stress responses between infants of depressed and non-depressed mothers," study leader Dr. Rima Azar, of Toronto General Hospital, said in a statement. Since the adrenocortical system is easily influenced in both positive and negative ways, Azar said she believes that it is very important to eventually identify which babies are more vulnerable to stress.