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For people with Down syndrome, family members, caregivers and professionals.

Attention Deficit / Hyperactivity Disorder (AD/HD)

December 2022 | Brian Chicoine, MD, and Dennis McGuire, PhD, LCSW - Adult Down Syndrome Center

*This article was adapted from Mental Wellness in Adults with Down Syndrome: A Guide to Emotional and Behavioral Strengths and Challenges, 2nd Edition.

What is attention-deficit/hyperactivity disorder?

Attention-deficit disorders are neurological disorders that have the following symptoms:

  • Problems with attention, 
  • Impulsive behavior, and
  • Distractibility.

Some individuals have primarily an inattentive presentation. Others have a primarily hyperactive/impulsive presentation. (Note that, in the DSM-5, both types of attention-deficit disorders fall under the umbrella category of attention-deficit/hyperactivity disorder, or AD/HD. To aid in making distinctions between the two subtypes, we will use the abbreviations ADD-In for AD/HD without hyperactivity and ADHD for AD/HD with hyperactivity.)  Additionally, some individuals have a combined type that has both inattentive and hyperactive/impulsive symptoms.

With studies showing prevalence rates at about 11 percent in children without an intellectual disability (Visser et al., 2014), AD/HD is one of the most common neurological conditions diagnosed in children. In children with Down syndrome, one study found a prevalence rate of 43.9 percent (Ekstein et al., 2011), although previous studies had found similar prevalence rates to children without Down syndrome (Cohen & Patterson,1998; Myers & Pueschel, 1991). Some clinicians have written that other conditions, including sleep problems, impaired vision and hearing, and thyroid disease, can look like AD/HD in children with Down syndrome (McBrien, 2012) and that AD/HD could therefore be misdiagnosed.

AD/HD often significantly impacts a child’s academic and work performance as well as their social and emotional functioning and development. Attention problems and distractibility may make it difficult for people to focus and follow through with essential tasks in an organized fashion. Additionally, because of impulsivity, relations with bosses and friends may suffer because the person may have trouble waiting or keeping comments to himself or herself. A child may also have difficulty concentrating on conversations, which may make it appear as if the child is disinterested in other people. Some individuals with this condition also have difficulty controlling their emotions and behaviors because of the impulsivity and may become aggressive when frustrated or stressed.

Childhood AD/HD has been recognized for many years, but only recently has it been found to affect a considerable number of adults. Adults may have the same problems with inattention, impulsivity, disorganization, and distractibility as children, and this may have the same effect on their social, emotional, academic, or occupational functioning as it does on children. Hyperactivity appears to be less common for adults with AD/HD, even in people who had hyperactivity as children. People may “grow out” of the hyperactivity as they age into adulthood.

Although there is no available research on the rates of attention-deficit disorders in adults with Down syndrome, we have evaluated a significant number of individuals who have this condition. This includes many individuals with a history of attention-deficit disorder with hyperactivity who seemed to grow out of the hyperactivity in adulthood. Like adults without an intellectual disability, they often continue to have problems with attention and impulsivity and therefore often benefit from medication to help them better manage these issues. We have also seen some adults with Down syndrome who continue to have hyperactivity, even though ADHD with hyperactivity is less common in adulthood in people without Down syndrome.

Symptoms of ADHD

What does ADHD (the hyperactive form of AD/HD) look like in adults with Down syndrome? To answer this question, it may be helpful to first describe typical symptoms in children. Although many children have high activity levels, children diagnosed with this disorder are so active that parents often describe them as “bouncing off the walls.” Adults with Down syndrome who have ADHD show some of the same overactive behavior that children show. Many have trouble sleeping, talk constantly and distractedly, and cannot stay still or focus long enough to do sports, activities, or essential school or work tasks. The level of activity in adults with Down syndrome may not be as intense as in children with ADHD (with or without Down syndrome), but, compared to other adults, their level is extreme. This type of behavior may be trying for caregivers of adults and children.

Is it ADHD or something else?

The good news about ADHD is that people get help because of the intensity of the symptoms and the impact on individuals and their caregivers. The symptoms simply cannot be ignored. Additionally, ADHD is a widely researched and known condition affecting children and adults. Because of this, teachers, pediatricians, and other practitioners are likely to diagnose this condition when a child or adult with Down syndrome is brought in with hyperactivity. The bad news about the widespread knowledge of ADHD is that hyperactive behavior may be diagnosed as ADHD when in fact the hyperactivity is caused by something else.

In reviewing referrals of people who have been previously diagnosed with ADHD, we have found that there is often an alternative explanation or diagnosis for the observed behavior. Accurate diagnosis may be even more of a challenge for people with Down syndrome who have a limited ability to verbally report problems or symptoms.

For example, in our experience, people with bipolar disorder may be misdiagnosed as having ADHD because manic behavior may look like hyperactive behavior. However, manic behavior is only a part of the symptom picture, and viewing it this way may lead to treatments that may worsen the problem. For instance, stimulant medications (which are often used to treat AD/HD) may increase manic behavior or increase the intensity of mood fluctuations. A careful history, which may be more likely to show the mood fluctuations (between mania and depression) that are characteristic of this disorder, can improve the accuracy of the diagnosis.

Similarly, mania may be misdiagnosed as ADHD. As with bipolar disorder, this may lead to the use of stimulants, which may worsen and intensify the mania. Mania is often a condition that occurs cyclically, and it often ebbs and flows, whereas ADHD is usually more consistent in symptoms and intensity level.

We have also seen people with autism spectrum disorders who were diagnosed with ADHD. Autism and ADHD can coexist in the same individual and both can coexist in a person with Down syndrome. Careful assessment is needed to decipher whether the diagnosis is ADHD, autism, or both. For example, some individuals may have hyperactive-like behavior, particularly when anxious or overstimulated. If the focus is only on the hyperactivity and diagnosing ADHD, overlooking key aspects of the autism disorder such as the lack of relatedness to others and communication impairment may lead to an inaccurate diagnosis. Without the correct diagnosis, individuals may not receive essential behavioral and medical treatment for the autism component.

Anxiety may also be easily misdiagnosed as ADHD. This is particularly the case for people with Down syndrome who may not be able to verbalize their feelings but express anxiety through agitated and overactive behavior. How do you sort out anxiety from ADHD? We recommend being particularly sensitive to the history and longevity of the symptoms presented. ADHD is present in early childhood and occurs throughout the person’s life. The intensity of the symptoms may change with age, but the disorder will still be present in some recognizable form in adulthood. On the other hand, if the person’s “hyper” behavior seems to begin during a stressful time, then it is more likely that the behavior is anxiety. Also, if the person’s ADHD occurs in only certain environments, such as a school classroom, this may mean that the environment is stressful. Often, we find that the person is either over- or under-stimulated in the stressful environment.

Finally, and perhaps most importantly, symptoms of ADHD may simply be the person’s preferred means of communicating behaviorally the presence of a stressful situation. Again, this is particularly likely for children and adults with Down syndrome who have limitations in verbalizing thoughts or feelings. Therefore, behavior that looks like ADHD may be communicating that there is a physical disorder, a sensory deficit (visual or auditory), a stressful change or loss, or an environmental stressor. As we emphasize when assessing for any behavioral change or psychological symptom, we can only get to the cause or source of a behavior if we, as practitioners and caregivers, become detectives and examine as many areas as possible, (e.g., physical, sensory, environmental, and life stage changes). This may be the only way to determine whether any other reasons or explanations for the person’s behavior are possible.

Symptoms of ADD-In

If ADHD is over-diagnosed, ADD-In (inattentive, without hyperactivity) is probably under-diagnosed. Children and adults with ADD-In are often far less disruptive and difficult to manage than those with ADHD. However, they may be far less likely to be diagnosed and treated for this condition. Studies have shown that a substantial number of children and adults without Down syndrome are not identified and treated for this condition because of the more subtle nature of the symptoms (especially when compared to people with hyperactivity) (Ginsberg et al., 2014; Jensen & Cooper, 2002; Murphy & Barkley, 1996). We have found that diagnosis may be even more of a problem for people with Down syndrome than for other groups. Aside from the difficulty of identifying symptoms, ADD-In may not be considered because it may be too easily attributed to Down syndrome, even when behaviors are not characteristic of Down syndrome (Reiss et al. 1982).

Children and adults with this condition may float along as if in a fog or dreamlike state. They have great difficulty concentrating on school or work tasks. They may have trouble in social situations because they have trouble listening to others or reading social cues. The distracted, dreamlike state may be even more of a problem for people with Down syndrome because they tend to have excellent visual memories, which they may draw on to “space out.” They may be teased by peers as being “space cadets” or “dreamers.” ADD-In may have a profound negative effect on the individual’s school, work, or social relations, and this in turn may have a disastrous impact on the person’s self-esteem.

Given the nature of the symptoms, how do we diagnose and treat ADD-In in people with Down syndrome? We have been treating adolescents and adults with Down syndrome for years, and yet we find this a challenging diagnosis that has the potential to be overlooked in people with Down syndrome. Still, we have found that several clues may help us, as well as caregivers and parents, identify ADD-In in this group. These clues relate to different symptom presentations in people with Down syndrome who have ADD-In compared to people with the disorder who do not have Down syndrome. There are also important differences between people with Down syndrome who do and do not have ADD-In that may be instructive.

First, regarding the presentation of symptoms, a key characteristic of people with ADD-In in people without Down syndrome is that they are often chaotic and disorganized. They often have great difficulty setting up and following consistent routines, making it difficult to do daily tasks reliably and efficiently. The resulting lack of a predictable order is often very frustrating for themselves and for family members.

We have seen a similar pattern for some people with Down syndrome who have ADHD (AD/HD with hyperactivity), but not for people who have ADD-In (without hyperactivity). These individuals have a sense of order despite having attention-deficit symptoms. They are often able to reliably complete daily living tasks, home chores, and work tasks, if these activities are part of their regular routine. Their routines and grooves then seem to carry them along despite their attention problems.

The key difficulty these individuals often seem to have is in dealing with free or unstructured time that is outside of their routine. This brings us to an important difference between people with Down syndrome who do and do not have ADD-In. In a nutshell, people with Down syndrome and ADD-In have great difficulty entertaining themselves. In our experience, this contrasts with most people with Down syndrome, who are usually very good at entertaining and occupying themselves during their free time.

Over thousands of interviews, we have repeatedly heard about adolescents and adults who have special activities they enjoy doing in their free time. Examples of these activities include drawing, copying words or letters, needlepoint, watching TV or movies, looking at family photographs, or even cleaning one’s room. In fact, most people with Down syndrome are so good at entertaining themselves that parents and caregivers often complain that they may spend too much time doing these activities. Therefore, when someone cannot do this, it should be a red flag for caregivers and practitioners, even if the person is otherwise able to follow daily routines.


Medications are an important part of the treatment for ADHD and ADD-In. The medications can help improve attention, reduce impulsivity, and reduce hyperactivity. The medications fall into two general categories: stimulant and nonstimulant.

Stimulant medications stimulate the central nervous system. Interestingly, this reduces the symptoms, including hyperactivity. The approved medications include methylphenidate (Concerta, Metadate, and Ritalin; also available in a patch, Daytrana), dextroamphetamine (Dexedrine), dexmethylphenidate (Focalin), and amphetamine/dextroamphetamine (Adderall). Side effects of stimulant medications in adults include nervousness, difficulty sleeping, motor tics, palpitations, loss of appetite, irritability, and others. Finding the right medication may take some time. Even if someone does not respond well to one stimulant, they may respond to one of the other medications.

The other choice is a nonstimulant medication. FDA-approved choices include atomoxetine (Strattera) for children and adults and guanfacine (Intuniv) for children. Atomoxetine inhibits the reuptake of the brain chemical norepinephrine, which is believed to play a role in regulating attention. It may cause side effects including sleep problems, fatigue, increased sweating, fatigue, palpitations, and others. Guanfacine stimulates alpha-2 adrenergic receptors, and side effects include low blood pressure, low heart rate, sleepiness, and others. Some people benefit from using a combination of a stimulant medication and guanfacine and/or atomoxetine. Bupropion (Wellbutrin) is an antidepressant that has also been used for ADHD and ADD-In. Clonidine (Catapres) is in the same class of medications as guanfacine and has been used for ADHD, but it does not have FDA (Food and Drug Administration) approval.


Cohen, W. I., & Patterson, B. J. (1998). Neurodevelopmental disorders in Down syndrome. In T. Hassold & D. Patterson (Eds.), Down syndrome: A promising future, together. New York: Wiley-Liss.

Ekstein, S., Glick, B., Weill, M., Kay, B., & Berger, I. (2011). Down syndrome and Attention-Deficit/Hyperactivity Disorder (ADHD). Journal of Child Neurology, 26(10), 1290–1295. 

Ginsberg, Y., Quintero, J., Anand, E., Casillas, M., & Upadhyaya, H. P. (2014). Underdiagnosis of attention-deficit/hyperactivity disorder in adult patients: A review of the literature. Primary Care Companion for CNS Disorders, 16(3).

Jensen, P. S., & Cooper, J. R. (Eds.). (2002). Attention Deficit Hyperactivity Disorder: State of Science—Best Practices. Kingston, NJ: Civic Research Institute.

McBrien, D. (2012). Attention problems in Down syndrome: Is this ADHD? University of Iowa Stead Family Children’s Hospital. Retrieved Sept. 3, 2020, from

Murphy, K. R., & Barkley, R. A. (1996). The prevalence of DSM-IV symptoms of AD/HD in adult licensed drivers: Implications for clinical diagnosis. Comprehensive Psychiatry, 37, 393–401.

Myers B.A., & Pueschel, S. (1991). Psychiatric disorders in a population with Down syndrome. Journal of Nervous & Mental Disorders, 179, 609–613.

Reiss, S., Levitan, G. W., & Szysko, J. (1982). Emotional disturbance and mental retardation: Diagnostic overshadowing. American Journal of Mental Deficiency, 86, 567–574.

Visser, Susanna, N. et al. (2013). Trends in the parent-report of health care provider-diagnosed and medicated attention-deficit/hyperactivity disorder: United States, 2003–2011. Journal of the American Academy of Child & Adolescent Psychiatry, 53(1), 34– 46.e2.

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