Aug. 16, 2001 -- Difficulty paying attention, school problems, and hyperactive behavior associated with ADHD -- attention deficit hyperactivity disorder -- are difficult enough. Many parents hesitate to add to their child's problems with medications that can have unpleasant side effects like Ritalin, so they turn to alternative therapies for ADHD like the dietary supplement docosahexaenoic acid, known as DHA.
Unfortunately, research reported in the August Journal of Pediatrics showed that the fatty acid DHA did not help ADHD symptoms.
"In our study conditions, we saw no effects of DHA on the symptoms of ADHD," researcher William C. Heird, MD, a professor of pediatrics at Baylor College of Medicine in Houston, tells WebMD. "It's possible that giving DHA for a longer period or in combination with other fatty acids might have been more helpful, but maybe it just doesn't work."
"We need a lot more research on dietary supplements, and this study is exactly the type of research that we need," Kathi J. Kemper, MD, MPH, tells WebMD. She is director of The Children's Hospital Center for Holistic Pediatric Education and Research in Boston, and wrote an editorial accompanying the study. "Alternative medicines have lots of potential, but very little proof."
As DHA tends to concentrate in the membranes of nerve cells, especially where they contact each other, Heird explains that DHA may affect electrical signaling in the brain. Earlier research suggests that brain levels of DHA are low in children with ADHD.
In the study, more than 60 children with ADHD randomly received either DHA or a placebo for four months. Although blood levels of DHA were twice to three times as high in those taking DHA, there was no difference between the two groups in psychological tests or rating scales by parents.
"We don't know for sure whether levels of DHA in the brain were higher in those who took the supplement, but it's a reasonable assumption," Heird says.
According to Heird and co-researcher Antolin M. Llorente, PhD, it is possible that arachidonic acid, which is also low in kids with ADHD, should have been added with the DHA. Another possibility -- fish oil containing other fatty acids in addition to DHA might have been more effective.
"It would be erroneous to conclude from this study that essential fatty acids are irrelevant to ADHD," agrees L. Eugene Arnold, MEd, MD, a professor emeritus of psychiatry at Ohio State University, who reviewed the study for WebMD.
Individual children might respond better to a particular fatty acid that they lack, Arnold explains. Of 250 children who applied for the study, the ones kept out because they did not respond to medicines like Ritalin might be the ones most likely to benefit from dietary supplements.
"Many parents choose alternative medicines to avoid side effects and expense," says Llorente, an assistant professor of pediatrics and psychiatry at Baylor. "Since makers of alternative medicines don't have to satisfy FDA requirements, we need more research like this to see whether their claims are [supported]."
"There are parents out there who feel that something they buy in a herbal food store is safer," says Julie Schweitzer, PhD, an assistant professor of psychiatry at the University of Maryland School of Medicine in Baltimore. "Unless we have more studies like these, we'll never how safe and effective they actually are."