Sep 6, 2010
Many parents, health care professionals, and educators agree that there is a pressing need to develop effective treatments for ADHD to complement or substitute for traditional medication and behavior therapy approaches. This is because such treatments do not work for everyone, important difficulties often remain even when these treatments are effective, and evidence for the long-term benefits of these treatments remains less compelling than one would like. In addition, in the case of medication treatment, some individuals experience intolerable side effects and many have concerns about taking ADHD medication for an extended period.
One alternative approach to treating ADHD has relied on the use of Compound Herbal Preparations (CHP) derived from traditional Chinese medicine. Practitioners of this approach believe that such preparations have important cognitive enhancing properties because they supply essential nutrients, fatty acids, phospholipids, amino acids, B vitamins, minerals, and other micronutrients that are important for optimal brain growth and development. As a treatment for ADHD, the idea is that many individuals with ADHD have deficiencies in essential nutrients that compromise healthy brain development and result in ADHD symptoms. Providing these nutrients via an appropriately prepared herbal compound thus has the potential to be therapeutic and reduce these symptoms.
This idea was tested recently in a randomized-controlled trial of a specific CHP for children with ADHD [Katz, Kol-Degani, & Kav-Venaki (2010). A compound herbal preparation (CHP) in the treatment of ADHD: A randomized controlled trial. Journal of Attention Disorders. Published online on March 12, 2010.] Participants were 120 6-12 year-old children newly diagnosed with ADHD based on a comprehensive diagnostic evaluation. These children were all evaluated at the Sheba Medical Center, one of the largest university-affiliated tertiary care centers in Israel.
(Editor´s note: Dr. David Rabiner, author of this article, previously reviewed a 2005 meta-analysis whose findings need to be kept in mind to contextualize this new study. In the article Dietary Intervention for ADHD: A Meta-Analysis, Dr. Rabiner concluded that “Results from this meta-analysis provide strong evidence that the behavior of children with ADHD can be made worse by dietary factors, and that eliminating AFCs from their diets will, on average, result in behavioral improvements. This result is consistent with with accumulating evidence that neurobehavioral toxicity may result from a wide variety of distributed chemicals.”)
Children were randomly assigned to receive either the CHP (n=80) or a placebo (n=40) that was specially prepared to taste, smell, and look similar to the herbal formula. Randomization was done in a 2:1 ratio because the treatment was to last 4 months, and investigators wished to minimize the number of children who would receive placebo treatment for which no benefit was anticipated.
Active ingredients in the CHP – brand name Nurture & Clarity – included Paeoniae Alba, Withania Somnifera, Centella Asiatica, Spirulina Platensis, Bacopa Monieri, and Mellissa Officinalis. All raw herbs used in the preparing the compound were approved by the Israeli Ministry of Health as safe, food-grade herbs.
Neither parents, children, research assistants who tested the children or staff members who distributed the appropriate formula to participants knew who received the CHP and who was given the placebo. To confirm that the placebo preparation could not be distinguished from the CHP, 20 Israeli medical students were provided with both preparations and asked which was which; these students were unable to reliably tell them apart. Based on the information provided, therefore, this appears to have been a carefully conducted trial with strong randomization and blinding procedures.
Prior to beginning treatment with the CHP or placebo, children were administered the Test of Variables of Attention (TOVA), a widely used computerized test of attention and impulsivity. In the TOVA, children sit in front of a computer and are instructed to respond using a particular key whenever a designated stimulus appears. When any other stimulus flashes they are not supposed to respond. The test lasts for over 20 minutes and good performance requires the child to sustain attention to an uninteresting task for a reasonably long period of time.
Failing respond when a response is required – errors of omission – are believed to reflect problems with sustaining attention. Responding when the wrong stimulus appears – errors of commission – reflect impulsive responding. Other measures from the TOVA include response reaction time and reaction time variability. Children receive a score on each scale that compares their performance to age-matched peers from a large normative sample. They are also assigned an overall score, again based on age appropriate norms.
Following baseline administration of the TOVA, children were treated with the CHP or placebo preparation over a 4-month period. At the end of 4 months the TOVA was administered a second time. This enabled the researchers to determine whether children receiving the CHP demonstrated significant improvement on the test compared to those who received placebo.
– Results –
At the follow-up assessment, data was obtained on 73 of 80 children who received the CHP compared to only 19 of 40 who received placebo. The significantly greater drop-out rate among placebo-treated children reflected the greater number of parents who were not satisfied with their child’s response and who withdrew to pursue other options.
Results from the TOVA were analyzed in 2 primary ways. First, within each group, researchers tested whether there was significant improvement from pre-test to post-test. Then, they directly compared CHP vs. placebo differences controlling for age and sex. Because preliminary analyses indicated that results were consistent across different ADHD subtypes, i.e., inattentive, hyperactive-impulsive, and combined, children with each subtype were combined in all analyses.
For the within group analyses, children in the CHP group showed statistically significant improvement on all indices of the TOVA. In fact, their average fell well within the normal range on all TOVA variables. In contrast, those in the placebo group showed small declines on each TOVA variable and continued to perform in the below average range.
A direct comparison of the two groups yielded equally strong results, as CHP- treated children made significantly greater improvement than placebo-treated children on every TOVA scale. The magnitude of these group differences would be considered large.
The authors conducted a final analysis in which they assumed that all control children who withdrew would have improved as much as the average child in the CHP group had they continued and that all CHP children who withdrew would not have improved at all. Even when these conservative assumptions were made, children in the CHP group were still performing significantly better on average.
It should also be noted that careful assessments were conducted during the 4-month trial on the safety and tolerability of the CHP. No serious adverse effects were reported and the rate of even mild adverse events among CHP-treated children was actually lower than for children who received placebo.
– Summary and Implications –
Results from this randomized-controlled trial of a compound herbal treatment for ADHD clearly indicate significant improvement on an objective measure of sustained attention and impulsive responding, i.e., the TOVA. Given how carefully the trial was conducted, and the magnitude of the effects that were found, this is an encouraging and impressive result. Beyond the TOVA results, the fact that over 90% of parents kept their child on the herbal compound over 4 months – compared to under 50% of children receiving placebo – suggests that they were observing real-world benefits in their child and were not receiving pressure from teachers to ‘do something’. Clearly, these findings underscore the potential benefits of this herbal compound in the treatment of ADHD.
Despite these impressive results, however, there remain several important reasons for caution regarding the potential benefits of this treatment. First, this is only a single study and replication with another sample would be important for increasing confidence in the findings. The need for replicating treatment effects is important for any treatment approach and hopefully such work is already underway.
Second, and I believe this is especially important, the outcome measures used to evaluate treatment impact were unfortunately limited. While the TOVA certainly offers objective evidence of improved attention and reduced impulsive responding, the measurement battery would have ideally included behavior ratings made by parents and teachers. Such ratings would provide a clearer indication than the TOVA results of whether treatment yielded reductions in ADHD symptoms that were observed at home and at school, which are the outcomes that really matter. Although the fact that most parents kept their child on the herbal compound for the 4 months suggests that ‘real-world’ reductions in ADHD symptoms were evident, collecting the standardized behavior ratings is necessary to confirm this.
Finally, the study provides no real information on how long any benefits of this treatment would be sustained. Is this compound something children need to take indefinitely – as is often true for medication – or do the benefits persist even after the compound is no longer administered? This would be important information to collect in subsequent work.
These limitations not withstanding, this is an interesting and important study that highlights the need for additional research on this promising intervention approach for children with ADHD.
– Dr. David Rabiner is a child clinical psychologist and Director of Undergraduate Studies in the Department of Psychology and Neuroscience at Duke University. He publishes Attention Research Update, an online newsletter that helps parents, professionals, and educators keep up with the latest research on ADHD, and teaches the online course How to Navigate Conventional and Complementary ADHD Treatments for Healthy Brain Development.