Slower childhood brain maturation may signal later anxiety and depression

Analysis of nearly 30,000 brain scans suggests delayed thinning of the cortex at age nine may be linked to anxiety and depression by early adolescence, although the finding cannot yet predict risk in individual children.

A child’s pace of brain maturation may offer an early clue to who is most likely to develop anxiety or depression in the teenage years, according to research published in Nature. The study, which analysed almost 30,000 brain scans, suggests that the timing of development may matter as much as where changes occur in the brain. Researchers said the findings point to a broader question in psychiatry: whether vulnerability to mental illness begins long before symptoms appear. Dr Avram Holmes, a systems neuroscientist at Rutgers University, said the work shifts attention towards “the timing of brain development, not just the location, when we look at psychiatric symptoms”.

The team, based at the University of Iowa and Mass General Brigham, followed children at roughly two-year intervals from the age of nine. They found that the cerebral cortex, the brain’s outer layer, thins in a predictable sequence as children grow, with sensory regions such as the visual cortex maturing earlier than frontal areas involved in attention, planning and emotional control. Children who had a thicker cortex in sensory regions at age nine were more likely to show anxiety and depression by age 13, suggesting that delayed cortical thinning may be linked to later mental health problems.

The findings fit with earlier studies showing that emotional difficulties in childhood can forecast later psychiatric symptoms. Research published in Scientific Reports found that anxiety and depressive symptoms reported in three-year-olds predicted similar problems at age eight, even when attention deficit hyperactivity disorder was taken into account. Other work has also linked maternal anxiety before and after birth to changes in infant brain development, particularly in the hippocampus, a region involved in stress regulation. Taken together, these studies support the idea that mental health risk can emerge through development over time, rather than appearing suddenly in adolescence.

The new analysis also dovetails with wider neuroimaging research suggesting that young people with mood and anxiety disorders do not all follow the same developmental path. Studies in Molecular Psychiatry have identified distinct brain maturational subtypes in adolescents with these conditions, while other research has found structural differences in brain regions including the prefrontal cortex, hippocampus and amygdala in children with anxiety disorders. Even so, the authors of the latest study cautioned that the patterns are only useful at a population level for now and are not ready for use in clinics to diagnose individual children. Dr Holmes said the work offers one of the clearest pictures yet of how the cortex develops from childhood into adolescence, but added that it is not sufficient on its own to predict illness for a single child.