Can Iron Play a Role in ADHD Diagnosis and Treatment?

The number of children being diagnosed with ADHD has grown tremendously over the last 15 years. According to the US Centers for Disease Control and Prevention, the percentage of children with an ADHD diagnosis continues to rise, from 7.8% in 2003 to 9.5% in 2007 and to 11.0% in 2011. There is vigorous debate as to what is causing the rise in diagnoses. The etiology of attention deficit hyperactivity disorder (ADHD) is attributed to different factors: genetic, environmental, and biological (specifically dopamine neurotransmitters). Iron plays a vital role, as it is essential for the correct functioning of dopamine hormones and neurotransmitters.

The U.S. National Institutes of Mental Health reports that thanks to brain imaging studies, scientists now understand that children with ADHD have brains that mature in a normal pattern but on a schedule that’s delayed by about 3 years. It is this delay that causes symptoms including hyperactivity, difficulty in paying attention and controlling behavior. These symptoms are usually controlled with some form of psychostimulant medication like Ritalin.

A recent study, published in the July 2014 edition of the Society’s journal Radiology and sponsored by the Radiological Society of North America, may help doctors more accurately diagnose children with ADHD and thus enable them to more effectively treat children with the disorder in a timely manner.

Currently, doctors rely on subjective clinical interviews and questionnaires in order to detect ADHD. The purpose of the study was to look at whether brain iron levels could offer a potential biomarker for more accurate diagnosis of ADHD, especially in borderline cases.

The research team measured brain iron levels in 22 children and adolescents with ADHD, 12 of whom had never been on medication for their condition, and 27 healthy control children and adolescents. The team used a magnetic resonance imaging (MRI) technique called magnetic field correlation imaging. This is a new technique introduced by the study’s co-authors in 2006. Iron levels in the body for all of the participants were measured by blood draws.

The study showed that the 12 ADHD patients who had never received medication had significantly lower brain iron levels than the 10 ADHD patients who had been on psychostimulant medication. Their brain iron levels were also lower than the iron levels of the 27 children and adolescents in the control group. In contrast, ADHD patients who had previous psychostimulant medication treatment had brain iron levels comparable to the controls. This suggests that brain iron may increase to normal levels with psychostimulant treatment.

"Our research suggests that iron absorption into the brain may be abnormal in ADHD given that atypical brain iron levels are found even when blood iron levels in the body are normal," said Vitria Adisetiyo, Ph.D., postdoctoral research fellow at the Medical University of South Carolina in Charleston, S.C. "We found no differences in blood iron measures between controls, medication-naïve ADHD patients or psychostimulant-medicated ADHD patients."

Scientists are continuing to study the relationship between iron and ADHD. Another recent study  suggests that blood iron levels can affect the severity of ADHD symptoms, since iron deficiency is common in patients with ADHD, and its correction may be useful in the treatment of the disorder.