MONDAY, May 4, 2020 (HealthDay News) -- Having a supportive family can significantly reduce a child's future risk of major depression, according to a new study.
Researchers analyzed data on more than 3,200 pairs of siblings in Sweden -- including more than 600 pairs of full siblings and nearly 2,600 pairs of half-siblings -- who had at least one biological parent with depression.
Each pair of siblings was raised apart, one at home and one adopted into a home with parents who could "provide a supportive and generally advantaged home for their adoptive child."
Being raised by an adoptive family in a supportive environment was associated with a 23% decrease in the risk of treated major depression among full siblings and a 19% decreased risk among half-siblings.
However, the reduction in the risk of major depression disappeared if another family member in the adoptive family -- a parent or step-sibling -- developed depression, or there was a death or divorce in the adoptive family.
If none of these events occurred, placement in a nurturing environment provided by the adoptive family resulted in a "protective effect" against depression, according to the study authors.
"No other study has examined the impact of parenting on risk for depression with this kind of powerful design -- having matched siblings who experienced quite different rearing environments," said co-lead author Kenneth Kendler, a professor of psychiatry at Virginia Commonwealth University.
"This design permits us to reach a stronger conclusion about causal effects than most other prior designs," Kendler explained in a university news release.
The study provides more evidence that both nature and nurture matter when it comes to depression and other psychiatric disorders, according to Kendler.
"In an era that tends to emphasize our nervous system's 'nature' through neurobiology, it is important to remember that basic family relationships -- high-quality parents who are caring and consistent -- can also impact in important ways our risk for psychiatric disorders," Kendler said.
The findings support "efforts to improve the rearing environment in high-risk families as an approach to the primary prevention of major depression," the authors wrote.
The study was published online April 28 in the American Journal of Psychiatry.
The U.S. National Institute of Mental Health has more on depression.
SOURCE: Virginia Commonwealth University, news release, April 28, 2020