Mother’s Depression Linked to Offspring Depression

Individuals whose mothers had depression while pregnant may have a higher risk of having depression at age 18 years, according to the results of a recent prospective cohort study. Postnatal depression was also found to be a risk factor for offspring depression at age 18 years, but only among mothers with lower levels of education.

Researchers noted in the study that understanding the link between maternal and offspring depression is important for prevention and intervention, as depression in late adolescence is a worldwide public health issue.

Previous studies have suggested that maternal postnatal and antenatal depression are associated with offspring depression, but these studies had small sample sizes.

“Large numbers are particularly important because, without a large sample, it is difficult separate the effects of antenatal and postnatal depression, so any associations between antenatal depression and offspring depression, for example, may exist only because the depression continues after birth,” said lead study author Rebecca M. Pearson, PhD, Centre for Mental Health, Addiction and Suicide Research, School of Social and Community Medicine, University of Bristol, England, in an interview with Consultant360. “We found some evidence that this was not the case because the patterns of risk were different according to whether the mother experienced the depression antenatally or postnatally.”

To investigate the hypothesis that there are independent associations between antenatal and postnatal depression in women with the later depression of their children and that the risk pathways are different, researchers analyzed data from more than 4500 community-dwelling parents and their adolescent children participating in the United Kingdom community-based Avon Longitudinal Study of Parents and Children.

“To our knowledge ours is the largest study to investigate these associations in a population,” said Pearson. “It is also the first study to have such a long follow-up (up to 18 years).”

Pearson and colleagues found that antenatal depression was an independent risk factor for offspring depression. Children were 1.28 times more likely to have depression at 18 years of age for each standard deviation increase in maternal antenatal depression score measured by the Edinburgh Postnatal Depression Scale, independent of later maternal depression.

Postnatal depression was a risk factor for offspring depression, but only among mothers with low education. Children of mother’s with lower education levels were 1.26 times more likely to have depression for each standard deviation increase in postnatal depression score. No association was found in those with higher education levels.

“These findings highlight that depression during pregnancy is important for both mother and offspring,” said Pearson. “Depression during pregnancy and after birth may confer different risks and should both be treated in their own right.” In addition, the authors noted in the study that it may be most effective to prioritize less advantaged mothers postnatally.

Pearson revealed that they were surprised by the extent to which maternal education was protective on the effects of postnatal depression.  

When questioned about the connection between maternal depression and low education, she hypothesized that this effect occurred “because low education is associated with several domains of environmental adversities, less social support, and lower income and access to resources, but also less knowledge of positive parenting practices. We think that higher education may buffer the effects of postnatal depression because the extra resources, knowledge, and support these mothers have may prevent depression from negatively affecting their parenting and thus their child.”  

Study limitations, as noted by Pearson, include the fact that the investigation was conducted in a relatively low-risk, quite advantaged sample.

Future steps in terms of research include investigating the protective role of education in more disadvantaged contexts to understand exactly how it is protective. For instance, “it is unlikely that education per se is protective, but rather it is a marker of something, such as parenting knowledge,” Pearson explained. “If we can understand the processes by which it is protective, this can inform intervention strategies for mothers without such educational advantages.”

The full results of this study, which was funded by the Wellcome Trust, the Medical Research Council, and the National Institutes of Health, are available online in JAMA Psychiatry.

-Meredith Edwards White

Reference

Pearson RM, Evans J, Kounali D, et al. Maternal depression during pregnancy and the postnatal period: risks and possible mechanisms for offspring depression at age 18 years. JAMA Psychiatry. 2013 Oct 9. doi: 10.1001/jamapsychiatry.2013.2163. [Epub ahead of print]