New research suggests that some mental illness like depression transmits biologically from generation to generation, even if parent and child do not share the same genetics.
Specifically, researchers believe, paternal depression is causing adolescent depression and behavior problems for the men’s children.
“A lot of research focuses on depression within biologically related families,” said Jenae Neiderhiser, Social Science Research Institute faculty member at Penn State. “Now more information is becoming available for adoptive families and blended families.”
The study used data from over 700 families, about half of which contained a child-rearing stepparent. Researchers wanted to capture the social dynamics of a child experiencing close parenting, i.e. a real fatherly experience, but without shared biology. Mothers, fathers and children each answered questions to measure symptoms of depression, behaviors and parent-child conflict. The researchers then examined the association between paternal depression symptoms and child behavioral symptoms in a series of models.
Childhood depression often presents itself as anger issues, defiance, and massive swings in eating or sleeping
“The results pointed squarely to the environmental transmission of depression and behaviors between fathers and children,” said Alex Burt, who has been collaborating on projects with Neiderhiser for two decades. “Additionally, we continued to see these associations in a subset of ‘blended’ families in which the father was biologically related to one participating child but not to the other, which was an important confirmation of our results.
“We also found that much of this effect appeared to be a function of parent-child conflict. These kinds of findings add to the evidence that parent-child conflict plays a role as an environmental predictor of adolescent behaviors.”
Neiderhiser admits that the results were expected by her team. While mental health issues may certainly contain an underlying biological component in the programming, common sense also says that human beings often absorb and reflect the environments in which they live daily. The surprising aspect of the study, according to Neiderhiser, was the absence of greater biological connection between parent and child. In other words, the depressive link between blended families was just as strong as biologically-related families. Nurture above nature, it would seem.
“It would be great to do more studies on step and blended families,” she said. “They tend to be an underutilized natural experiment we could learn more from to help us disentangle the impacts of environmental factors and genetics on families.”
Depression affects about 3 percent of children in the United States.
Children with depression often experience many of the same depression symptoms as teens and adults do. However, children may have a hard time expressing themselves and these feelings because of their limited emotional vocabulary.