Iron Levels in the Brain Might Signal ADHD in Youths

ADHD diagnosis may be possible with MRI measuring iron levels in the brain

(RxWiki News) There has been a debate about ADHD and whether it's overdiagnosed. To date, there has not been an objective way to diagnose the condition, but new research may change that.

A recent study found that children and teenagers who were diagnosed with ADHD (attention deficit hyperactivity disorder) and had never used psychostimulant medication had significantly lower levels of iron in their brain than medicated ADHD patients and people without ADHD.

The researchers believe that brain iron levels could help doctors diagnose ADHD in a non-invasive manner, as well as help determine what treatment, if any, is needed.

"Discuss ADHD testing with your child's pediatrician."

The lead author of this study was Vitria Adisetiyo, PhD, from the Center for Biomedical Imaging and the Department of Radiology and Radiological Science at the Medical University of South Carolina in Charleston, South Carolina.

The study included 22 children and teenagers with ADHD and 27 controls (comparison subjects) without the condition.

ADHD is a common disorder among children and teenagers that can continue into adulthood. Symptoms include hyperactivity and difficulties staying focused and paying attention.

All the participants were between the ages of 8 and 18 years old and were recruited from the New York University Child Study Center, Medical Center and the local community between June 2009 and April 2011.

Of the participants with ADHD, 10 had a history of taking psychostimulant medications, such as Ritalin, and 12 of them had never been medicated.

Psychostimulants work to reduce ADHD symptoms through dopamine regulation. Dopamine plays a part in motor control, motivation and reward associated with certain tasks.

The researchers used a type of magnetic resonance imaging (MRI) to measure the iron levels in the participants’ brains.

MRI is a noninvasive diagnostic technique that uses magnetic fields and radio waves to create detailed images of the organs and tissues in the body.

Blood samples were also taken to measure iron levels in the blood.

The findings showed that the 12 non-medicated participants had significantly lower levels of iron in their brain than the 10 participants with a history of psychostimulant use and the control group.

The 10 medicated ADHD patients and the control group had similar levels of brain iron. The researchers suggested that this similarity indicated that psychostimulant treatment increased brain iron to normal levels among ADHD patients.

The findings also revealed that despite the differences in brain iron levels, all the participants had similar levels of iron in their blood.

"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," Dr. Adisetiyo in a press statement.

An ADHD diagnosis is typically based on interviews and questionnaires. The researchers suggested that brain iron may be a biomarker (biological sign of disease) of ADHD that can help doctors objectively diagnose the condition, especially in borderline cases.

The research team noted that these findings could help doctors determine which patients would benefit from psychostimulants. This is an important consideration because psychostimulants can be addictive when used incorrectly.

Dr. Adisetiyo and team concluded that more research is needed to verify the results of this study.

"We want the public to know that progress is being made in identifying potential noninvasive biological biomarkers of ADHD which may help to prevent misdiagnosis," Dr. Adisetiyo said. "We are currently testing our findings in a larger cohort to confirm that measuring brain iron levels in ADHD is indeed a reliable and clinically feasible biomarker."

This study was limited by the researchers' inability to determine whether the findings in the medicated ADHD patients were due solely to psychostimulant use because two of the patients also had a history of using medications that were not psychostimulants.

In addition, the study population was small and the data were recorded at one point in time, so the researchers could not determine a cause-and-effect relationship between psychostimulant medication and brain iron levels, or if the effects on brain iron were affected by treatment duration.

This study was published on June 16 in Radiology.

The National Institutes of Health provided funding.

Review Date: 
June 19, 2014