Having a depressed parent is one of the strongest predictors of depression in youth. In fact, half or more of the children of clinically depressed mothers experience depression as well as other mental health disorders later in life.

Though the link between maternal and child depression has been well established, many questions remain unanswered. For example, are more severely depressed mothers more likely to have depressed children? Are children whose mothers are depressed in their infancy more likely to become depressed than children whose mothers are depressed later in their childhood? And how does the duration of the mothers’ depression factor in?

In a study published in the March 2003 Archives of General Psychiatry , researchers reported that greater severity of maternal depression increased the likelihood of adolescent depression and that children exposed to one to two months of maternal major depression or more than 12 months of mild maternal depression were also at elevated risk.

About the Study

The 816 mother-child pairs were selected from a large cohort study of children born between 1981 and 1984. The mothers were selected based on their depression scores on the Delusions-Symptoms States Inventory (DSSI). They were tested during pregnancy, after delivery, when the child was six months old and when the child was five years old. The researchers used these scores to select study participants with and without depression. They also determined the severity and frequency of subjects’ depression.

The present study was conducted when the children were 15 years old.

In this study, the initial data was used to reclassify the severity and frequency of depression according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Researchers categorized each period of depression according to severity, duration, and timing (whether it occurred when the child was newborn–2 years old, 3–5 years old, or 6–10 years old).

The Findings

Children who were exposed to mothers with major depression, dysthymic disorder (frequent or constant depressed mood), or minor depression by age 10 were significantly more likely to have experienced major depression or dysthymia by age 15 compared to children of nondepressed women (20.1% versus 10.2%). These children were also significantly more likely (10.7% versus 4.9%) to have anxiety disorders.

After controlling for demographic factors such as gender and family income, severity of maternal depression was found to contribute more strongly to a child’s risk of depression than the duration of the depression. Children exposed to one to two months of maternal major depression or to more than 12 months of mild maternal depression had an elevated risk of depression. The timing of the maternal depressive episode did not seem to affect the child’s risk of depression.

This study was limited by its small sample size; though there were 816 mother-child pairs in the study, the number of mother-child pairs in each category of severity, duration, and timing was smaller. Another limitation was the study’s focus on exposure to maternal depression during only the first 10 years of a child’s life, rather than the first 15 years.

How Does This Affect You?

This study underscores the effect that maternal depression can have on the mental health of children. It strongly suggests that women who are struggling with depression—even mild depression—should seek treatment. It also highlights the need for physicians and other health professionals to identify mothers with depression and get them into treatment programs.

At the same time, the absence of a link in this study between brief periods of mild maternal depression and a child’s mental health should reassure women who experience mild, but brief, periods of depression.

Finally, the study did not find the timing of a child’s exposure to maternal depression to be significant. This suggests that postpartum depression , which may affect as many as 10% of new mothers, is no more risky than depression at any other time.