Predicting Children’s Response to Methylphenidate (Ritalin)

One of the questions asked most frequently is how parents can know whether medication particularly Ritalin will help their child.  It would certainly be helpful to know in advance whether a particular child truly will benefit from medication, what the magnitude of those benefits will be, and what areas (e.g. behavior, academics, etc.) will be most effected. 

 A study appearing in an issue of the Journal of the American Academy of Child and Adolescent Psychiatry takes a careful look at how well medication response can be predicted in advance (Denney, C.B. & Rapport, M.D. (1999). Predicting methylphenidate response in ADHD. Journal of the American Academy of Child and Adolescent Psychiatry, 38, 393-401.)  In this study, 76 children with ADHD, Combined Type (i.e. they had both inattentive and hyperactive/impulsive symptoms) received each of 4 doses of methylphenidate (MPH - this is the generic form of Ritalin) in the context of a double-blind, placebo-controlled medication trial.  There were 66 boys in the sample and 10 girls.

 Both before and during the trial, careful measures of a number of behavioral and academic variables were collected.  These included teacher ratings of inattention and hyperactivity using standardized behavior rating scales; direct observations of children's on-task behavior in the classroom made by observers blind to the child's medication status; teacher ratings of children's self-control in both the academic and social areas; and finally, a measure of academic efficiency which was defined as the percentage of assigned work that the child completed in an accurate manner.  The authors were particularly interested in whether any of the behavioral or academic measures collected prior to the medication trial would prove to be helpful in predicting whether or not the child showed a positive response to medication, and whether it could predict the optimal dose for each child.

 Although there was some variation depending on what outcome measure was being predicted (e.g. inattention, hyperactivity, self-control, academic efficiency), overall, predicting whether an individual child would benefit from medication based on any of the pretreatment variables was quite difficult.  There was some indication that the more inattentive and/or hyperactive a child was to start with, the more likely he or she is to show gains in these areas.  In other words, children whose ADHD symptoms were more severe were more likely to show positive effects from medication.

 What seems to me to be a more interesting and important aspect of the results, however, was the finding that behavioral improvements do not necessarily lead to corresponding academic improvements. Thus, it was not uncommon for a child to show clinically significant gains in the core ADHD symptoms, and yet not to show corresponding gains in the academic efficiency measure. In other words, for some children, their behavior improved but their academic performance did not.

 In contrast to this pattern, gains in academic efficiency were almost always accompanied by corresponding improvements in attention, hyperactivity, and self-control. Thus, when children's school work improved, their primary ADHD symptoms almost always improved as well.   

Was there any way to predict which children would show these important gains in the academic efficiency measure? It turns out that there was, and that the best predictor was how well a child was performing academically prior to starting the medication trial.  Children whose pre-treatment academic efficiency scores fell in the bottom 50% were much more likely to show improvements in academic functioning than children whose pre-treatment academic scores were higher.  These latter children, however, might still show important gains in the areas of core ADHD symptoms.

 What does this all mean?

 First, the findings highlight that assessing a child's response to medication should be a fine-grained process. One can not assume that gains in one area will necessarily mean gains in all areas.  As this study demonstrated, there can be many children who show important gains in behavior without corresponding gains in academic performance.

 For each child, therefore, one has to carefully monitor the effects of medication in multiple domains of functioning. Thus, you would want to know what impact medication is having on behavior, social relations, and academic performance to have a clear understanding of the child's unique response. 

 This assessment of medication's impact on different areas should be evaluated in comparison to the domains that were most problematic to begin with.  Thus, if academic functioning is the chief concern, it is very important to evaluate how the child's academic work is changing in response to medication.  What you don't want to do is assume that just because your child may be behaving better in class, that his or her school work is also better.

 Parents and teachers can be understandably elated that a child's behavior is under better control, and the fact that the child's school performance is still not very good manages to be overlooked.  When report card time rolls around, there can be some unfortunate surprises in store.

 By the way, this same approach can, and should, be used to evaluate a child's response to any type of treatment. Thus, if you are considering alternative methods for treating your child (e.g. behavioral interventions, herbal treatments, etc.) you would still want to carefully track what effect - if any - the treatment is having in different areas.  You would also want to pay careful attention to whether the areas of real trouble are the ones that are being positively affected.


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