Study finds that childhood developmental disorders in the brain begin before birth

"We found those relationships to be more complex than we had imagined. For example, genetic risk for ADHD and depression were associated with a range of symptoms in children, not just those related to attention or mood," co–senior author Joshua Roffman, MD, director of MGH's Early Brain Development Initiative, said in an MGH statement. "The genetic factors that shape mental illness symptoms in kids differ from the ones that shape mental illness symptoms in adults."

Identifying these gene expressions, which the researchers call a "neurodevelopmental gene set", has also been shown to predict the risk of childhood psychiatric symptoms in children enrolled in a study in the Netherlands known as Generation R.

Data analysis from brain banks shows that genes in the neurodevelopmental gene set tend to be most strongly expressed in the brain's cerebellum, tied to motor function, and their expression peaks before birth. Data from the ABCD Study also shows that children with psychiatric symptoms generally had a somewhat smaller cerebellum, which may indicate the influence of these genes on the brain in a more physical way.

"That genetic risk factors for mental illness in kids begin to influence the brain so early on—even before birth—means that interventions that protect them from risk may also need to start earlier in life than previously expected," Roffman said. "It is also important to note that while genes play an important part in risk for mental illness, the early life environment is also critical—and at this point, potentially easier to modify."

"Our research team at Mass General is searching for other factors during pregnancy—whether in the realm of healthy lifestyle (such as quality sleep, exercise, and diet), optimal prenatal care, or psychosocial support—that can confer resiliency in developing brains and protect against risk of psychiatric disorders in young people," Roffman added.