Adoptees Have Slightly Higher Genetic Risk for Mental Illness
Adopted children have an increased risk for depression, anxiety and other mental health disorders. Research has primarily attributed this to stressful early childhoods, but a new study finds that genetics also plays a role.
“We found adopted individuals on average had a somewhat higher genetic risk for mental health problems, but the effects are quite small,” said lead author Kelli Lehto, Ph.D., a postdoctoral researcher at Karolinska Institute in Stockholm. “Overall, the main message here is that both environment and genetics are important.”
The findings are published in the journal Biological Psychiatry.
Psychiatric disorders, including depression, anxiety and schizophrenia are, to varying degrees, heritable. Genome-wide association studies (GWAS) have identified a growing number of genetic markers associated with the risk for most major psychiatric disorders so that a “polygenic risk score” for these disorders may be estimated.
In the new study, the research team analyzed the genomic and health information data of 243,797 participants in the UK Biobank, a major health resource established by the Wellcome Trust and others. The data included 3,151 people who were adopted as children within Britain, mostly in the 1950s and 1960s.
Overall, the adoptees reported being happy and satisfied with their lives. When compared to the general population, they were more likely to be male, to smoke, have less education, attain a lower income, and to experience more stressful life events. Adoptees also had slightly more mental health problems, such as depressive symptoms, bipolar disorder, higher neuroticism and loneliness.
The researchers found that adoptees had a slightly elevated genetic risk of depression, schizophrenia and neuroticism. But although children put up for adoption were at increased genetic risk for developing symptoms of mental illness, the adoption process did not appear to increase the impact of this genetic risk.
“Basically, genetic risk and adoption each are predictors of psychiatric problems,” said Lehto. “It’s important to highlight that adoption and genetic risk each only contributed a small amount to the individual differences in mental health. That indicates many more factors contribute to the development of mental health problems.”
The findings may apply to other types of childhood adversity and adult mental health outcomes among non-adoptees, she added.
“There are many complicated issues to consider in these findings,” said John Krystal, M.D., editor of Biological Psychiatry. “But the most straightforward implication is that adopted children may face both special environmental and genetic risks for adjustment problems and mental illness. Awareness of these risks increases the importance of programs aimed at early detection and intervention for these children.”
Pedersen, T. (2020). Adoptees Have Slightly Higher Genetic Risk for Mental Illness. Psych Central. Retrieved on September 27, 2020, from https://psychcentral.com/news/2020/02/02/adoptees-have-slightly-higher-genetic-risk-for-mental-illness/153890.html