Postnatal depression linked to depression in offspring until age 16

Fortunately, postnatal depression often resolves itself in the weeks following childbirth. But for mothers with more profound or prolonged postnatal depression the risk of subsequent development of depression in their children is strong. A recent study by Lynne Murray and colleagues published in the May 2011 issue of the Journal of the American Academy of Child and Adolescent Psychiatry (JAACAP) is the first to demonstrate that the effects of maternal depression on the likelihood of the child to develop depression may begin as early as infancy.

In the article titled "Maternal Postnatal Depression and the Development of Depression in Offspring Up to 16 Years of Age," Dr. Murray and her British colleagues report on 100 mothers (ranging from 18 to 42 years of age), 58 with postpartum depression, and the likelihood of their children to development depression over a 16 year period.¹ The authors identified first time mothers with depression at 2 months postpartum, along with a group of non-depressed women, and evaluated the mothers and their children at 18 months, and 5, 8, 13, and 16 years of age.

Maternal depression was assessed using the SPI at recruitment, the Schedule for Affective Disorder and Schizophrenia, and the Structured Clinical Interview for DSM-IV. At each assessment, marital conflict was assessed using a combination of interview and questionnaire tools. At 18 months, infant attachment was assessed, using a standardized observational measure of infant responses to maternal separation and reunion in an unfamiliar environment, known as Ainsworth's Strange Situation Procedure. At 5 and 8 years, trained researchers rated the children on emotional and behavioural responses to assess their ego resilience. At 16 years, diagnostic interviews were conducted by a clinical researcher blind to maternal state using the Kiddie Schedule for Affective Disorders and Schizophrenia, Present and Lifetime Version (KSADs).

Murray and colleagues discovered that children of postnatally depressed mothers were at substantially increased risk for depression. In fact, offspring's rate of depression by age 16 was more than 40%, with the average age of first onset of depression at age 14. Interestingly, the researchers found that some years before the onset of depression, an associated impairment of the children's attachment to their mother during infancy. In addition, lower child ego resilience, measured at years 5 and 8, were associated with the increased risk of depression. Marital conflict and further maternal depression, extending beyond the postnatal period, were significantly associated with offspring lifetime depression.

In a related editorial in the same issue of the Journal, Dr. David Reiss observes, "The striking findings from Murray et al. emphasize the impact of maternal depression on the marital process and how important this process in the evolution of the child's depression.²

The researchers conclude, "The substantially raised risk for depression among offspring of postnatally depressed mothers underlines the importance of screening for PND and of delivering early interventions."