Infants at familial risk for depression show a distinct pattern of cortisol response to experimental challenge

The aim of the study was to examine the link between maternal depression and the infant's HPA axis functioning in relation to a sequence of emotional challenges at 12 months postpartum, while controlling for maternal anxiety disorder and general sociodemographic risk.

Two hundred and fifty-seven infants whose mothers had been interviewed in pregnancy, as part of a prospective longitudinal study of a nationally representative sample of U.K. families, were individually tested in the laboratory and then observed during a simulated birthday party scenario. Three cortisol samples were taken over the course of 1½ h of afternoon testing.

The cortisol levels of infants whose mothers had no history of depression decreased significantly after individual testing, and rose again significantly in response to the birthday party challenge. In contrast, infants whose mothers had been diagnosed with depression before conception, during pregnancy or in the first 6 months postpartum showed no decrease from the initially elevated levels at entry to the laboratory and a less marked increase in response to the party.

The study does not employ a traditional stress paradigm; instead it introduces a novel design to assess HPA axis functioning in relation to everyday emotional challenges.

The findings suggest that altered responses to mildly challenging events in infancy may be a marker for infants' familial risk for depressive illness.