by Tracy Packiam Alloway, PhD
To medicate or not? Research in children with ADHD.
Published on March 21, 2011
The topic of medicating individuals with ADHD is still controversial. That is why I am always interested when research on this topic is published. I was recently asked to write a commentary on one such article that will appear in ‘Developmental Medicine and Child Neurology'.
Children with ADHD exhibit deficits in both cognitive and behavioral domains. In particular, response inhibition has been proposed as a core element of individuals with ADHD that can impact both these types of functioning. Given the widespread prevalence of ADHD, with some reports as high as 16% of children receiving this diagnosis, treatment is a priority.
Stimulant medication, such as methylphenidate, is considered to improve certain cognitive functions in children with ADHD. The suggestion is that methylphenidate acts to increase levels of dopamine and norepinephrine, which are associated with attention and focus.
However, most research in this area has focused primarily on immediate-release stimulant medication. Clinical studies in continued-release of stimulant medication have produced mixed results and it is as yet unclear which cognitive and behavioral functions associated with response inhibition can be improved as a result of stimulant medication.
Thus, the authors-Blum et al-sought to investigate this issue. Children aged 6 to 12 participated in a double-blind placebo controlled crossover trial, using the individual's most effective dose of OROS- methylphenidate. The benefit of this approach is that neither the person administering the medication, nor the child taking it was aware of whether they were receiving the medication or the placebo. The conditions were then switched, so the Medication group took the placebo, and the Placebo group took the medication.
The findings indicated that hyperactive and inattentive behaviors (measured by both parent and teacher ratings) improved when the child was receiving their optimal dose of OROS- methylphenidate. Cognitive functions also improved in some cases, but not all. For example, the students were no better at tasks involving motor inhibition and working memory.
Studies like this one by Blum et al. are very valuable because they raise the issue of the efficacy in using this approach for individuals with ADHD. Amidst increasing concerns regarding side effects and the potential for abuse, some parents and clinicians are seeking alternative methods to ameliorate the cognitive and behavioral deficits associated with ADHD.
One promising alternative is adaptive working memory training, where the intensity and difficulty of working memory sessions are individually customized to the aptitude of the child. Traditionally, working memory was viewed as genetically fixed, and thus unable to be modified by an individual's environmental experiences or opportunities. However, an increasing body of recent studies has challenged this notion, demonstrating that considerable cerebral plasticity exists within the developing brain and that working memory capacity may potentially be improved by environmental intervention and support.
Such findings highlight important opportunities for improving the learning, behavioral and social opportunities of the large number of children with working memory problems. Working memory impairments are widely reported in students with ADHD, and several studies have found that adaptive working memory training can improve behavior ratings by parents (Klingberg et al., 2005), as well as IQ and attainment scores (Alloway, 2009).
Research like Blum et al.'s illustrates the limited impact of continued-release of stimulant medication and highlight the need to consider alternative forms of intervention. When such measures prove to be insufficient, then the option to prescribe stimulant medication can be discussed with a physician who is aware of the severity of the individual's symptoms. Care should also be taken when considered the type of stimulant medication-immediate vs. continuous release; as well as the optimal dose for the individual.
References
Alloway TP. Cognitive Training: Improvements in Academic Attainments. Professional Association for Teachers of Students with Specific Learning Difficulties 2009; 22: 57-61.
Klingberg T, Fernell E, Olesen PJ, Johnson M, Gustafsson P, Dahlstrom K. et al. Computerised training of working memory in children with ADHD -a randomized, controlled trial. J of the Am Acad of Child and Adolescent Psychiatry 2005; 44: 177-186.
Article retrieved from: http://www.psychologytoday.com/blog/keep-it-in-mind/201103/adhd-and-medication-whats-new
Image retrieved from: http://www.thetwentyfirstfloor.com/main/wp-content/uploads/2011/02/ADHD-boy.jpg
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