Parents’ genetic traits might indirectly influence a child’s risk for anxiety and depression

A child’s risk of developing anxiety and depression is influenced not only by the genes they inherit, but also by the genetic traits their parents possess. A large study published in Nature Mental Health found that a mother’s genetic likelihood for smoking and a father’s genetic propensity for general well-being help predict a child’s mental health outcomes over time. These results illustrate how a parent’s DNA can shape a child’s environment, creating indirect genetic pathways that affect youth emotional development.

Depression and anxiety are categorized as internalizing problems, which involve directing distress inward. These conditions often take root during childhood and adolescence. Researchers wanted to understand exactly how much of a child’s mental health risk comes from their own biology versus the environment their parents create. Disentangling these two factors is exceptionally difficult because biological parents provide both the home environment and the DNA of their offspring.

Scientists refer to the influence of a parent’s genes on a child’s environment as an indirect genetic effect, or genetic nurture. For instance, if a parent has a high genetic likelihood for depression, that biological trait might influence their parenting style or the emotional stability of the household. The child might then develop anxiety or depression as a reaction to that environment, rather than purely because they inherited the specific genes for those conditions.

Researchers led by Razieh Chegeni, a psychologist at the University of Oslo in Norway, conducted the research to separate these tangled pathways. By looking at a broad spectrum of genetic scores across whole families, the team sought to map how different genetic traits in parents and children combine to influence mental health risk. They were specifically interested in seeing how these patterns change as children grow from middle childhood into adolescence.

To investigate this, the researchers analyzed data from 9,314 parent and child trios, classifying it as a large study. The participants were part of the Norwegian Mother, Father and Child Cohort Study. The team utilized 90 polygenic scores to assess the genetic propensities of the mothers, fathers, and children. A polygenic score is a tool that estimates a person’s genetic likelihood for a specific trait based on thousands of tiny variations across their DNA.

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The researchers calculated polygenic scores for a variety of traits beyond just mental health. These included body mass index, intelligence, attention-deficit hyperactivity disorder (ADHD), smoking habits, and cognitive skills. They then used an advanced statistical technique to sort through these highly correlated variables. This allowed them to identify which combinations of genetic scores best predicted the child’s symptoms of depression and anxiety at age 8 and again at age 14.

When looking at depression at age 8, parental genetics played a heavy role. A mother’s genetic likelihood for having multiple sexual partners or experiencing depression was linked to higher depressive symptoms in the child. The researchers note that these maternal genetic traits might act as proxies for a more unpredictable home environment or reduced emotional availability, which can negatively affect a young child.

As the children reached age 14, their own genetic traits became more influential in shaping their mental health. The child’s own polygenic scores for cognitive skills and ADHD emerged as prominent risk factors for depression in adolescence. A high genetic liability for ADHD often involves challenges with emotional regulation and impulse control, which can naturally elevate the risk of developing depressive symptoms as teenagers navigate complex social environments.

Throughout both developmental stages, a father’s genetic likelihood for general well-being acted as a consistent protective factor against depression. A father with a genetic disposition toward positive psychological traits may contribute to a more resilient and supportive family environment. Unsurprisingly, the child’s own genetic propensity for well-being also insulated them against depressive symptoms at both age 8 and age 14.

For anxiety, the predictive patterns looked slightly different. The mother’s genetic likelihood for smoking cigarettes was the strongest indirect risk factor for the child’s anxiety at both assessed ages. The researchers suggest this might reflect how genetic tendencies toward stress regulation difficulties in mothers can create a sustained environmental vulnerability for the child.

The child’s own polygenic score for well-being provided the strongest protective effect against anxiety across both time points. In contrast to its effect on depression, a child’s genetic liability for ADHD was associated with protection against anxiety. The researchers explain that this aligns with previous studies showing that temperaments with high novelty-seeking and low harm-avoidance are often linked to lower anxiety levels.

The study also examined how the genetic traits of family members might interact with one another. They found that shared genetic likelihoods between both parents for certain cognitive and non-cognitive skills were associated with higher depressive symptoms in their offspring. This highlights how shared traits between partners might compound to create specific family dynamics that influence a child’s emotional health.

Despite the large study size, the total variance in mental health symptoms explained by the polygenic scores was small. The models explained a maximum of 2.7 percent of the variance in depression and 1.2 percent of the variance in anxiety. This small explanatory power means that current polygenic scores are scientific tools for understanding broad population trends, rather than practical clinical tests for predicting a specific person’s future mental health.

The genetic data originated primarily from people of European descent in Norway. Broadening this research across different global populations and ancestries is required to see if these developmental patterns apply to humans universally. Additionally, the genetic scores used for the children were calculated based on adult data, which might not perfectly match how those genetic pathways express themselves during the earlier stages of childhood.

Finally, the researchers note that these associations are observational. The correlations do not confirm that the genetic factors directly cause the specific mental health outcomes, as other unmeasured environmental variables could be at play. Future research will need to incorporate direct observations of parenting styles alongside genetic data to build a more complete picture of how nature and nurture shape youth mental health.

The study, “Direct and indirect parental genetic effects on offspring susceptibility to internalizing problems across development,” was authored by Razieh Chegeni, Ragnhild Bang Nes, Rosa Cheesman, Ziada Ayorech, Eivind Ystrøm, and Espen Røysamb.