ADHD in childhood is a fairly common disorder. ADHD is a disorder in which the child exhibits decreased attention span, impulsive behavior, excessive fidgeting, and other nondirected motor activity. At some time throughout childhood, all children, even those children with Down syndrome, exhibit these traits. In children with Down syndrome, the symptoms of ADHD can mean that a medication needs to be adjusted, there is an underlying medical problem that needs to be addressed, or the child's educational process needs to be adjusted. For children with Down syndrome, ADHD is a diagnosis of exclusion.

There are some medical problems that can look like ADHD in a child with Down syndrome. Hearing a vision problems are quite common in children with Down syndrome. In order for a child to pay attention in a classroom or educational setting, he or she must be able to see and hear what is going on. When there are problems with one or both of these senses, the child can develop traits that are similar to that of ADHD. The child should be evaluated by an ENT (ear, nose, and throat) doctor as well as an eye doctor to identify if there is indeed a medical problem to address.

About 30% of all children with Down syndrome will have thyroid problems at some point in their lifetime. Hypothyroidism or under active thyroid is the most common form of thyroid disorder in children with Down syndrome. However, there are medical conditions that cause overactive thyroid in Down syndrome patients as well. In any case, the symptoms can be agitation, restlessness, and apathy in the child. It is recommended that children with Down syndrome get annual blood tests to check for thyroid inefficiencies.

Sleep disorders are extremely common in children with Down syndrome. Sleep disorders clearly cause a lack of adequate sleep, which in a child can cause restlessness, whiny attitude, and difficulty calming down. Sleep disorders also need to be ruled out before diagnosing ADHD in a child with Down syndrome.

Children with Down syndrome can have many difficulties with communication. If material is presented in a way that is not compatible with a child's learning style, the child will become fidgety, restless, and inattentive. The level of the material can also cause these same symptoms if the child is not on the same level. The child could be bored with material that is too easy or confused over material that is too difficult.

If the child has had a thorough medical examination and everything has shown to be clear, and the traits of inattentiveness and agitation persist then a diagnosis of ADHD should be considered. ADHD has been found to be less common in children with Down syndrome however, the medications used to treat ADHD have been found to be equally affective in both situations. Since sleep problems are common in children with Down syndrome and ADHD medications can cause sleep problems, the child should be watched to make certain he or she is getting adequate rest at night.