Although stimulant medication is a well-established treatment for ADHD, it is often necessary
for doctors to increase the dose over time to maintain the benefits of the medication. While
medication can be very effective for improving symptoms of ADHD during the first year of use,
it has not been found to significantly improve the long term course of children with ADHD.
For example, in large research studies, groups of children who take medication for ten years
do not have consistently better academic grades than groups of children who never used
medication (individual results will vary from child to child).
In order to help children with ADHD achieve the best possible outcomes, it is important for
doctors to study why this happens. One possible reason is development of tolerance to the
medication. Tolerance means that a drug's effects decrease when it is taken consistently over
time, so that an increased dose is needed to continue showing effects. Some doctors believe
that children who take stimulant medication for ADHD develop tolerance to it which would
explain why benefits may not persist over time, but no research studies have been done to
measure whether this occurs. This study aims to see if children show a tolerance effect to
stimulant medication and whether that tolerance can be prevented by taking short breaks from
the medication called medication holidays.