According to a study conducted by the National Institutes of Health, children with attention-deficit/hyperactivity disorder (ADHD) experience a developmental delay in frontal regions of the brain.

The study is published in Biological Psychiatry.

The team examined 234 children with ADHD and 231 normally developing children. Each child’s brain was scanned up to four times from age 10 to 17. The team then used advanced neuroimaging technology in order to map the trajectories of surface area development at over 80,000 points across the brain.

The surface area of the cerebral cortex – the folded gray tissue that makes up the outermost part of the brain – grows during childhood. However, the researchers discovered that this process was delayed in frontal brain regions in children with ADHD.

According to the researchers, the normally developing children attained 50% peak area in the right prefrontal cortex at a mean of 12.7 years compared with 14.6 years for children with ADHD.

Dr. Phillip Shaw, a clinician studying ADHD at the National Institute of Mental Health explained: “As other components of cortical development are also delayed, this suggests there is a global delay in ADHD in brain regions important for the control of action and attention.”

Dr. John Krystal, Editor of Biological Psychiatry, said: “These data highlight the importance of longitudinal approaches to brain structure. Seeing a lag in brain development, we now need to try to understand the causes of this developmental delay in ADHD.”

Dr. Shaw explained that the study finding “guides us to search for genes that control the timing of brain development in the disorder, opening up new targets for treatment.”

Further research expanding these measures into adulthood will also be vital. Such data would help determine whether or when a degree of normalization occurs, or if these delays translate into long-lasting cortical deficits.

Written by Grace Rattue