What if some of the risk of anxiety and depression in children is not only about the genes they inherit, but also about their parents’ genetic dispositions and how these influence the home environment?
In a new study of more than 9,300 Norwegian families, researchers at the Department of Psychology, University of Oslo, find that children’s mental health is linked both to their own genetic dispositions and to those of their parents – probably because parents’ genetic vulnerabilities can also shape the home environment in which the child grows up.
Transfer across generations
The effects are small, the researchers emphasise, but the findings provide new knowledge about how psychological vulnerability can be transmitted across generations.
"We have long known that parents matter greatly for children’s mental health. What is new in our study is that we can show this using genetic data from the mother, father, and child at the same time", says Razieh Chegeni of the PROMENTA Research Centre.
She is the lead author of the study, which is published in Nature Mental Health. The researchers analysed genetic data from 9,314 Norwegian families taking part in the Norwegian Mother, Father and Child Cohort Study (MoBa). The aim was to examine how children’s mental health is related both to their own genetic dispositions and to those of their parents.
Parents’ genes influence the home environment
"The most interesting finding is that children’s symptoms of anxiety and depression do not seem to be linked only to their own genetic dispositions. The parents’ genetic profiles also appear to play a role", explains Chegeni.
Parents’ genetic dispositions can affect how their children are doing, how they regulate emotions, and how everyday life functions at home, she continues. In this way, parents’ genetic vulnerabilities can also influence the environment in which the child is raised. According to Chegeni, these are called indirect genetic effects.
The study thus shows that children’s mental health is shaped both by their own genes and by their parents’ genetic profiles, which in turn affect the home environment.
Interactions change over time
However, this did not look the same at all ages. Some genetic factors were more important in childhood, while others became more evident during adolescence. The associations were stronger at age 14 than at age 8, suggesting that the impact of genes and the home environment changes from childhood to adolescence.
On the parents’ side, the mother’s genetic vulnerability to smoking and the father’s genetic disposition for psychological well-being stood out in several of the models. Chegeni stresses that these factors alone do not explain children’s mental health, but that such genetic profiles can point to traits and vulnerabilities that also affect the family around the child.
At the same time, the researchers are clear that this is not a tool for predicting mental health in individual children. Even the best models explained only up to 2.7 per cent of the variation in depressive symptoms and 1.2 per cent of the variation in anxiety.
"Genes are not destiny. Our findings cannot be used to predict mental health in individual children, but they can help us to better understand how risk is transmitted across generations", concludes Chegeni.