WASHINGTON, Aug. 1 (UPI) -- Researchers found combining therapies for attention deficit hyperactivity disorder is more effective than individual therapies on their own, according to a series of recently published studies.
Three studies conducted at the University of California Los Angeles, and published in the Journal of the American Academy of Child and Adolescent Psychiatry, suggest that combining two standard therapies may be an improvement over their individual efficacy.
While some improvements were seen in study participants, researchers say better treatment methods are needed for children with ADHD, especially with regard to their long-term progress.
The studies explored the potential of combining the stimulant d-methylphenidate, commonly known as Ritalin, with the drug guanfacine, which is marketed as Tenex and Intuniv and used for both high blood pressure and for ADHD treatment.
In one study, researchers recruited 182 children between the ages of 7 and 14, dividing them into three groups and treating them with either d-methylphenidate, guanfacine or a combination of the two. A control group of 93 children also were recruited as a baseline measurement.
The researchers reported that while the combination group showed improvement in working memory compared to placebo or guanfacine by itself, there was no significant improvement over treatment with d-methylphenidate by itself.
The second study had 207 participants, also between the ages of 7 and 14, who were treated with the same three methods: d-methylphenidate, guanfacine or a combination of the two, with efficacy of the treatments measured using the ADHD Rating Scale IV and the Clinical Global Impression−Improvement.
Based on the two scales, the researchers report the combination therapy was superior to the individual drugs, with few adverse health events or concerns of safety and tolerability.
For the third study, the researchers recruited 179 participants between the ages of 7 and 14 who were split into the same three groups. The researchers measured differences in brain waves using electroencephalography before the study, during and then after medication was stopped to measure behavioral and cognitive function.
While the researchers note differences could be found with all three courses of treatment, the greatest difference in both behavioral and cognitive function was with the combination treatment. The benefit of EEG measurements of participants, they add, is the ability to see how the drugs affected patients.
Overall, the researchers report clinical response from participants increased from about 63 percent with one drug to 75 percent with the combination, a good response.
Despite seeing these differences, the researchers say short-term benefits may not be ideal, because they do not know how the therapy will continue to work over the long term -- requiring more research, better drugs and longer studies.
"ADHD is the most commonly diagnosed neuropsychiatric disorder in children, and we know full well the risks it poses for children's future success in every area of functioning," Dr. James McCracken, a research at UCLA, said in a press release. "While we are encouraged by some of the advantages we observed of the combined treatment, we have a long way to go still in improving interventions for ADHD, as seen by the more limited cognitive effects."