New ADHD Findings

During the last two months, several new studies have provided a better understanding of attention deficit hyperactivity disorder, a condition that often becomes apparent in preschool and early school years. The National Institute of Health’s National Institute on Drug Abuse has documented decreased dopamine activity in the brain for those with ADHD. Dopamine is a chemical messenger in the brain involved in governing movement, emotional response, and the ability to feel pleasure and pain. Drugs of abuse- alcohol, cocaine, marijuana and others, temporarily increase the concentration of dopamine in the brain. For this group , taking drugs is not for getting high but to improve brain functioning and temporarily perform better. (www.reuters.com/article/latestCrisis/idUSN03330661)

A genetically determined pattern of brain development has also been linked to ADHD. Children with ADHD who had a particular genetic variation started out with an unusually thin cortex in the parts of the brain important for attention. Overtime, their brains appeared to normalize. Symptoms that were there at age 8 disappeared by age 16. This study is the first to confirm that ADHD is a real neurological disorder affecting 3-5% of school age children. (www.technologyreview.com/Biotech/19197/)

Scientists have, for the first time, conclusively confirmed what parents have long suspected. There is a connection between hyperactivity and food additives. The study, published online by Lancet, the British medical journal, found that a mix of additives commonly found in children’s foods increases hyperactivity. The study focused on a variety of food colorings and on sodium benzoate, a common preservative. In a six week trial a randomly selected group of 3 year olds and of 8-9 year olds had drinks with these additives, equivalent to one or two days serving of candy. The diet was otherwise controlled for other additives. All children received pre and post testing for inattention and hyperactivity. Both the control group and those taking the additives in both age groups were significantly more hyperactive and with shorter attention spans than before the study. More investigation is planned to study which components caused the effect. (“Some Food Additives Raise Hyperactivity, Study Finds”, Elisabeth Rosenthal, The New York Times, 9/6/07).

Eye convergence problems have also been found to mimic ADHD. Dr. David Granet, professor of ophthalmology and pediatrics at the University of California, San Diego, studied 266 patients with convergence insufficiency (CI). Nearly 10% also had a diagnosis of ADHD- 3 times that of the general population. Further study looked at the records of 1,700 children with ADHD. 16% had convergence insufficiency. Granet pointed out that five of the ADHD symptoms overlapped with CI. Dr. Stuart Danker, a pediatric ophthalmologist and assist clinical professor at Johns Hopkins, noted that CI is not the cause of most attention and reading problems but that an eye exam should be done as a part of comprehensive testing. (“Not Autistic or Hyperactive, Just Seeing Double at Times’, Laura Novak, The New York Times, 9/11/07).