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

A recent study in Nature Mental Health reveals that a child's risk for anxiety and depression may be indirectly influenced by the genetic traits of their parents. Researchers from the University of Oslo found that genetic likelihoods for conditions such as smoking in mothers, and well-being in fathers, can shape a child's environment, leading to indirect genetic pathways that affect emotional development.

These mental health issues, categorized as internalizing problems, often originate during childhood and adolescence. The challenge for researchers lies in determining how much of a child's risk stems from their own biology versus the environment created by their parents.

Researchers utilized data from 9,314 Norwegian families to investigate this phenomenon. They analyzed 90 polygenic scores, which estimate a person's genetic predisposition to specific traits, including mental health, body mass index, intelligence, ADHD, smoking, and cognitive skills. The study revealed that at age 8, parental genetics had a significant impact on the child's depression risk.

For example, a mother's genetic predisposition towards multiple sexual partners or depression was linked to higher depressive symptoms in the child, possibly acting as a proxy for an unpredictable home environment or reduced emotional support. By the age of 14, the child's own genetic traits for cognitive skills and ADHD became more influential in shaping their mental health.

ADHD, often associated with challenges in emotional regulation and impulse control, can increase the risk of depression during teenage years.

Interestingly, a father's genetic predisposition towards general well-being consistently served as a protective factor against depression in children. Additionally, the child's own genetic well-being traits provided protection against depressive symptoms at both ages. For anxiety, the strongest indirect risk factor was the mother's genetic likelihood for smoking, likely due to difficulties in stress regulation that create a vulnerable environment.

Conversely, a child's genetic well-being trait acted as a protective factor against anxiety. The study also noted that shared genetic traits between parents, particularly for cognitive and non-cognitive skills, correlated with higher depressive symptoms in their children, suggesting that shared traits can compound to influence family dynamics.

Despite the study's large size, the polygenic scores explained only a small portion of the variance in mental health symptoms, indicating that they offer insights into broad population trends rather than individual predictions.