January 30,2014 — Summary of "The Long-Term Effects of Maternal Depression: Early Childhood Physical Health as a Pathway to Offspring Depression," Raposa et al., Journal of Adolescent Health, January 2014.
Current research suggests that "maternal depression puts some children at risk for health problems during early childhood, and these difficulties with physical health might in turn lead to increased rates of depression in offspring," according to Elizabeth Raposa of the Department of Psychology at the University of California-Los Angeles and colleagues.
However, "few studies have acknowledged the interplay between offspring physical health and mental health outcomes by examining childhood physical health as one potential pathway from maternal depression to offspring depression," they wrote.
They developed a study to "examin[e] the longitudinal relationships among maternal depression, offspring physical health, and offspring depression," as well as to "explor[e] two potential mechanisms of the effects of offspring physical health on later depression: ongoing health-related stress and problems with social functioning."
The researchers studied a sample of mother-child pairs from a much larger study of children born between 1981 and 1984 in Queensland, Australia.
When the youth were 15 years old, 815 mother-child pairs were selected from the birth cohort, based on mothers' self-reported levels of depression and anxiety. The sample was over-selected for maternal depression relative to the general population but was otherwise similar to the larger cohort.
The mothers also completed questionnaires on their depressive symptoms post-partum and during their offsprings' early childhood and provided information on offsprings' physical health in infancy and early childhood.
The researchers periodically measured youths' ongoing stress, disability associated with physical health, social functioning and depressive symptoms. The final follow-up at ages 22 to 25 included 475 youth from the original sample of 815.
For the analysis, the researchers created models with various controls to test their hypothesis that maternal depression would indirectly affect youth depression via poor health in early childhood.
One model controlled for youth depressive symptoms at age 15, "given the fact that depressive symptoms are associated with both social functioning at age 20 and youth depressive symptoms at ages 22-25." Another model controlled for family income at age 15 because it could be tied to both decreased access to health care and increased depressive symptoms, according to the researchers.
To explore whether observed effects were attributable mainly to children's chronic illnesses, the researchers created a third model that "was identical to the first, but did not include childhood chronic illness in the childhood physical health composite."
The researchers found that "[p]renatal maternal depressive symptoms had a significant indirect effect on offspring depressive symptoms in young adulthood."
The study determined that maternal depressive symptoms during pregnancy were directly related to increased health problems for youth prior to age five and indirectly affected offspring health problems via ongoing maternal depression in early childhood.
In turn, offspring health problems predicted increased health stress and poorer social adjustment for offspring at age 20, which itself predicted concurrent difficulties with social functioning. Those two factors -- health-related stress and poor social functioning -- predicted higher youth depressive symptoms at ages 22 through 25, the researchers determined.
The pattern of effect held when researchers controlled for youth depressive symptoms and family income levels at youth age 15. Moreover, the model held when researchers controlled for a lack of chronic illness by youth age 5, except in that childhood physical health at age 5 was no longer a direct predictor of poor social functioning at age 20. However, childhood physical health still predicted health-related stress and disability at age 20, which in turn predicted poor social functioning.
The study shows "that poor childhood physical health is one pathway by which maternal depression affects youth depression in young adulthood," the researchers wrote, adding that it also shows that "ongoing stress related to physical health and poor social functioning in young adulthood are two mechanisms by which childhood physical health affects later youth depression."
They noted that maternal depression and childhood physical health were linked "even in children with no history of early childhood chronic illness, indicating that maternal depression can lead to more general health problems early in life."
The findings "have important implications for clinical interventions in children of depressed mothers," such as how interventions "might improve the developmental trajectories of at-risk children" and youths' "psychosocial outcomes later in life," according to the researchers.