Risk of major depression decreases 23% in ‘supportive’ home environment, researchers find

A drawing of two houses. The house on the left is colored in dark blues and greys and a dark clou...
In a paper published by the American Journal of Psychiatry on Tuesday, researchers found that being raised by an adoptive family in a harmonious and stable rearing environment was associated with a 23% decrease in risk for major depression versus being raised at home in a less stable environment. (Graphic by Ellie Erhart, University Relations)

Home environment has a significant impact on children’s likelihood of developing major depression later in life, researchers state in an American Journal of Psychiatry paper published today.

Researchers at Virginia Commonwealth University and Lund University in Malmo, Sweden, found that being raised by an adoptive family in a supportive environment led to a 23% decrease in risk of treated major depression among full siblings and a 19% decrease in risk among half-siblings.

Lead authors Kenneth S. Kendler, M.D., director, professor and eminent scholar at the Virginia Institute for Psychiatric and Behavioral Genetics at VCU, and Kristina Sundquist, M.D., a professor of family medicine and clinical epidemiology at Lund University in Malmo, Sweden, co-wrote “The Rearing Environment and Risk for Major Depression: A Swedish National High-Risk Home-Reared and Adopted-Away Co-Sibling Control Study” with two Lund University co-authors.

Using data from the Swedish National Sample, the study followed 3,262 pairs of siblings — 666 pairs of full siblings and 2,596 pairs of half-siblings — who had at least one biological parent with depression. The authors state in the paper that each pair of siblings was raised apart, one at home and one adopted into a home screened for parents who could “provide a supportive and generally advantaged home for their adoptive child.”

Title text on the screen says "Risk of Depression Between Siblings Raised Apart." On-screen caption reads "Being raised by an adoptive family in a harmonious and stable rearing environment was associated with a 23% decrease in risk for major depression versus being raised at home in a less stable environment."
Researchers found that being raised by an adoptive family in a harmonious and stable rearing environment was associated with a 23% decrease in risk for major depression.

If another family member in that adoptive family — a parent or stepsibling — developed depression or a death or divorce occurred in the adoptive family, the reduction in risk for major depression disappeared, the authors stated. If none of these situations occurred, the placement in a nurturing environment provided by the adoptive family resulted in a “protective effect” against depression, according to the researchers.

“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 Kendler, the Rachel Brown Banks Distinguished Professor of Psychiatry in VCU’s School of Medicine. “This design permits us to reach a stronger conclusion about causal effects than most other prior designs.”

According to the World Health Organization, more than 264 million people worldwide suffer from depression, and the National Institute of Mental Health estimates that 17.3 million U.S. adults — 7.1% of all American adults — had at least one major depressive episode in 2017.

The study solidifies the argument that both nature and nurture — the genetics of nature and the life experiences of nurture — matter when it comes to depression and other psychiatric disorders, Kendler said.

“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.

Two portrait drawings show a figure in dark colors showing sadness on the left and a figure in bright colors showing happiness on the right. 

Title text states "Risk of Depression Between Half-Siblings Raised Apart." On-screen caption reads
Findings in the paper state that half-siblings adopted into a stable home environment had a 19% decrease in risk for major depression versus being raised in a less stable environment. (Graphic by Ellie Erhart, University Relations)

The authors said these findings support “efforts to improve the rearing environment in high-risk families as an approach to the primary prevention of major depression.”

“Dr. Kendler and his colleagues have increased the world’s knowledge of the relationship between home environment and major depression in a profoundly important way,” said Michael Rao, Ph.D., president of VCU and the VCU Health System. “This research will give insights into how parents individually and societies globally can provide loving and nurturing environments to support the well-being of children as they grow into adulthood.”

“Dr. Kendler is one of the world’s most respected researchers, and he ranks among the top 100 most-cited scientists in the world,” according to a database of the 100,000 most-cited scientists from 1996-2017, said P. Srirama Rao, Ph.D., vice president for research and innovation at VCU. “His contributions to our understanding of behavioral genetics are unrivaled, and VCU is rightly proud of his groundbreaking research.”

Researchers received funding from the National Institutes of Health, the Swedish Research Council and Region Skane in Sweden to complete this study.

About VCU and VCU Health

Virginia Commonwealth University is a major, urban public research university with national and international rankings in sponsored research. Located in downtown Richmond, VCU enrolls more than 30,000 students in 233 degree and certificate programs in the arts, sciences and humanities. Twenty-two of the programs are unique in Virginia, many of them crossing the disciplines of VCU’s 11 schools and three colleges. The VCU Health brand represents the VCU health sciences academic programs, the VCU Massey Cancer Center and the VCU Health System, which comprises VCU Medical Center (the only academic medical center in the region), Community Memorial Hospital, Children’s Hospital of Richmond at VCU, and MCV Physicians. The clinical enterprise includes a collaboration with Sheltering Arms Institute for physical rehabilitation services. For more, please visit www.vcu.edu and vcuhealth.org.