Risk for depression and other disorders is known to be high among children of depressed mothers, but little is known about the parameters of severity, chronicity, and timing of depression and its effects on children. The study addresses these issues, disaggregating their overlapping effects.
A sample of 816 women and their 15-year-old children in an Australian community were selected from a large birth cohort study to represent variation in maternal depression history during the child's first 10 years of life. Quantification of maternal depression severity and duration, and dates of occurrence, permitted analyses of youth depression and nondepressive disorders as a function of relative severity, chronicity, and timing of maternal depression.
Diagnosable depression in children as old as 15 years was twice as likely among offspring of depressed, as compared with never-depressed mothers. After controls for demographic factors, severity of maternal depression contributed more to children's risk for depression than did chronicity. Children exposed even to 1 to 2 months of maternal major depression, or to more than 12 months of mild depression had elevated risks of depression; however, chronicity of maternal depression was associated more with nondepressive outcomes than was severity. Timing of exposure did not differentially predict risk for the disorder in children when separated from confounding chronicity and severity parameters.
Even relatively brief maternal major depression, but more prolonged mild depression, predicted children's risk for depressive disorders by age 15 years in a community sample. Nondepressive outcomes were more complex to predict, which was due in part to difficulty dating disorder onset in relation to maternal depression. Exposure to maternal depression at any period in the first 10 years equally predicted youth depression if the mother was depressed only once. Further studies are needed to shed light on the mechanisms by which maternal depression has its effects.