Although stimulant medication treatment has
been shown in hundreds of studies to produce significant reductions in ADHD
symptoms, it's impact on children's academic outcomes remains unclear.
Certainly, research has shown that medication treatment frequently yields
short-term improvements in the accuracy and amount of academic work that
children complete. However, documenting that this translates into long-term
gains in academic achievement has remained elusive. This is an important
gap in the literature because problems with academic achievement are a frequently
occurring difficulty in children with ADHD.
A study published in a recent issue of the Journal of Attention Disorders [Barnard,
L., et. al., (2010). The importance of ADHD subtype classification for educational
applications of DSM-IV. Journal of Attention
Disorders, 13, 573-583] offers perhaps the most careful examination
to date of how stimulant medication treatment impacts academic achievement
over time. As such, this is an important study to be aware of.
Participants were drawn from a nationally representative study commissioned
by the US Office of Special Education Programs to examine academic outcomes
in students eligible for special education services. From the nearly
10,000 6-12 year old youth in this sample, 2844 carried a diagnosis of ADHD.
All participants were administered a standardized test of academic achievement
- the Woodcock Johnson III - that evaluated their achievement in reading
and math in relation to age-match national norms. The WJ-III was administered
3 times over a 4-year period. This enabled the researchers to examine
how children's level of academic achievement changed over time.
- Diagnosis of ADHD
It is important to understand how children were identified with ADHD in this
study. Parents were simply asked whether their child had been diagnosed
with "...attention deficit disorder or attention deficit hyperactivity disorder?
These are sometimes called ADD or ADHD." If parents responded affirmatively,
this diagnosis was confirmed with the child's school, as it would be part
of the educational record for children receiving special educational services.
The important point here is that there was no independent verification that
the diagnosis given to the child was correct, and it is likely that many
children may have been misdiagnosed. The implications of this point
will be evident below.
- Medication treatment
To measure stimulant treatment status, parents were asked at 3 time points
whether their child was receiving medication treatment for ADHD. Children
taking medication at all 3 time points were considered the 'treated' group
and those never receiving medication were considered the 'untreated' group.
Children receiving treatment at 1 or 2 of the time points were not included
so that a 'pure' group of treated and untreated children could be compared.
Children in both treated and untreated groups received whatever educational
supports would have been provided in their schools to students with ADHD
and are assumed to have been equivalent across groups. Thus,
comparisons of their academic achivement indicate benefits that may have
been associated with medication treatment above and beyond whatever other
services they were receiving.
The researchers were interested in how medication treatment might impact
academic achievement in children with the 3 different subtypes of ADHD -
the inattentive type (children with significant attention difficulties but
fewer problems with hyperactive and impulsive behavior), the hyperactive-impulsive
type (children with significant hyperactive and impulsive behavior but fewer
attention difficulties) and the combined type (children with both attention
problems and hyperactive-impulsive behavior).
To identify subtypes, the researchers examined teacher ratings on items that
asked about the different types of ADHD symptoms. These ratings were
used to group children into each of the 3 subtypes, depending on which types
of symptoms were most prominent. Of course, this is not an ideal method
for accurate subtyping, but was the best the researchers could do given the
data that was available to them.
Interestingly, 17% of the children did not show prominent elevations of either
inattentive or hyperactive-impulsive symptoms, even though they were reported
to have an ADHD diagnosis. Thus, they did not fit into any of the 3
subtypes, and were instead classified as having ADHD, NOS (not otherwise
Because these children did not show the kind of significant problems with
inattention or hyperactive-impulsive behavior that is generally seen at school
in children with ADHD, it must also be considered that they had been incorrectly
diagnosed in the first place. Or, they may have simply had a milder
form of the disorder.
- Results -
Compared to untreated children, those receiving medication treatment generally
showed significantly greater gains in academic achievement over time.
However, this was only true for children in the 3 well-defined subtypes of
ADHD, i.e., inattentive, hyperactive-impulsive, and combined, and not for
those in the NOS group.
Medication treatment appeared to be associated with greater achievement gains
for children with high levels of attention problems - those with the inattentive
or combined subtypes - compared to the gains made by those with the hyperactive-impulsive
subtype. Thus the gains associated with medication treatment were twice
as large for inattentive children than hyperactive-impulsive children, and
nearly three times as large for children with the combined subtype compared
to the hyperactive-impulsive subtype. In all cases, however, the gains
were small to moderate in magnitude.
Interestingly, not only did children in the ADHD, NOS group fail to show
significant benefits from medication treatment, but treatment for this group
was actually associated with reduced academic achievement over time.
And, the magnitude of the negative effect was as large as any of the positive
effects found for medication treatment in the other 3 subtypes.
and Implications -
This is an important study for several reasons. First, it is one of
the few studies to show that ADHD medication treatment provided over an extended
period is associated with significant gains in children's academic achievement.
The fact that this was found in a large and nationally representative sample
of children treated in the community, and not as part of a carefully conducted
research study, is also noteworthy. This implies that sustained medication
treatment as provided in community settings can have positive effects on
children's academic performance. Thus, the authors suggest that the
"...overall implication for parents and practitioners is ... that stimulants
are not just for the management of behavior but can be associated with positive
academic outcomes also."
Of course, it should be emphasized that these positive findings in no way
suggest that consistently administered medication treatment is all that children
need to promote their academic success. As noted above, the magnitude of
the gains associated with medication treatment were modest at best, and specific
academic supports will be required by many children with ADHD in order to
achieve at a level consistent with their potential.
The negative association between medication treatment and children in the
ADHD, NOS group is also important and a reason for concern. Recall that children
in this group failed to show extreme teacher ratings for either attention
problems or hyperactive-impulsive behavior, suggesting that they either had
a milder form of ADHD or that they had been incorrectly diagnosed.
Two possibilities are suggested. First, stimulant medication treatment
in children with milder variants of ADHD may not be advisable as it could
be associated with reduced academic achievement over time. Why this
might be the case, however, is unclear.
A second possibility, and my own view is that this is more likely, is that
when children are incorrectly diagnosed with ADHD, medication treatment may
hurt their performance over time because whatever actual difficulties they
have are not being addressed. For example, if a child with a learning
disability is misdiagnosed with ADHD and treated with medication, he/she
would not receive the specialized academic supports/instruction required
to help them make good academic progress.
Despite the interesting nature of these findings, there are important limitations
to this study that should be recognized. Most noteworthy is that standardized
diagnostic evaluations were not conducted on many of the children, which
is likely to introduce error into the findings. Related to this is
that the researchers had to rely on teachers' ratings of a small number of
behaviors to assign children to the different ADHD subtypes, which is far
from ideal and would also introduce error. This was a limitation of the data
set was available for the authors to work with, and was not something they
These shortcomings notwithstanding, results from this study highlight the
need for careful diagnosis as well as the need to carefully monitor how medication
treatment may affect children's academic achievement over time. Although
encouraging evidence was provided that such treatment can help enhance some
children's long-term academic achievement, not all children diagnosed with
ADHD will show such benefits and some are actually likely to be harmed.
Information presented in Attention Research Update is for
informational purposes only, and is not a substitute for professional medical
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