Attention Deficit Hyperactivity Disorder (ADHD) is so commonly diagnosed – and overdiagnosed, and misdiagnosed – that it is hard to know what is based on evidence and what is based on teachers and concerned parents reacting to children that don't like to sit around and do nothing.
Actual clinical ADHD used to be rare but now it is a common problem of "pill culture" in psychiatry and the most common behavioral disorder label given to children in America, according to the Centers for Disease Control and Prevention.
Without reliable physiological markers to diagnose ADHD, it is just symptom-based medicine, which medicine stopped doing 50 years ago and the National Institute of Mental Health would like to end for psychiatry as soon as possible. Instead of using science, it is diagnosed by recording the medical and social history of the patient and the family, discussing possible symptoms and observing the patient's behavior. It has led to over-medication with Ritalin (methylphenidate), which even 1960s speed freaks worried about taking.
A new study from Tel Aviv University researchers may provide an objective tool that medical professionals need to accurately diagnose ADHD. According to the paper in Vision Research, involuntary eye movements accurately reflect the presence of ADHD, as well as the benefits of medical stimulants that are used to treat the disorder.
Keeping an eye on the eyes
Dr. Moshe Fried, Dr. Anna Sterkin, and Prof. Uri Polat of TAU's Sackler Faculty of Medicine, Dr. Tamara Wygnanski-Jaffe, Dr. Eteri Tsitsiashvili, Dr. Tamir Epstein of the Goldschleger Eye Research Institute at Sheba Medical Center, Tel Hashomer, and Dr. Yoram S. Bonneh of the University of Haifa used an eye-tracking system to monitor the involuntary eye movements of two groups of 22 adults taking an ADHD diagnostic computer test called the Test of Variables of Attention (TOVA).
The exercise, which lasted 22 minutes, was repeated twice by each participant. The first group of participants, diagnosed with ADHD, initially took the test un-medicated and then took it again under the influence of methylphenidate. A second group, not diagnosed with ADHD, constituted the control group.
"We had two objectives going into this research," said Dr. Fried, who as an adult was himself diagnosed with ADHD. "The first was to provide a new diagnostic tool for ADHD, and the second was to test whether ADHD medication really works – and we found that it does. There was a significant difference between the two groups, and between the two sets of tests taken by ADHD participants un-medicated and later medicated."
Foolproof, affordable, and accessible diagnosis
The researchers found a direct correlation between ADHD and the inability to suppress eye movement in the anticipation of visual stimuli. The research also reflected improved performance by participants taking methylphenidate, which normalized the suppression of involuntary eye movements to the average level of the control group.
"This test is affordable and accessible, rendering it a practical and foolproof tool for medical professionals," said Dr. Fried. "With other tests, you can slip up, make 'mistakes' – intentionally or not. But our test cannot be fooled. Eye movements tracked in this test are involuntary, so they constitute a sound physiological marker of ADHD.
"Our study also reflected that methylphenidate does work. It is certainly not a placebo, as some have suggested."
The researchers are currently conducting more extensive trials on larger control groups to further explore applications of the test.