Ask the Cognitive Scientist

Understanding ADHD

How does the mind work—and especially how does it learn? Teachers' instructional decisions are based on a mix of theories learned in teacher education, trial and error, craft knowledge, and gut instinct. Such gut knowledge often serves us well, but is there anything sturdier to rely on?

Cognitive science is an interdisciplinary field of researchers from psychology, neuroscience, linguistics, philosophy, computer science, and anthropology who seek to understand the mind. In this regular American Educator column, we consider findings from this field that are strong and clear enough to merit classroom application.

Question: What can you tell me about ADHD? Is it even real—or is it just a faddish diagnosis? How can I recognize it in a student—and how can I help a student who has it?

Answer: ADHD, short for Attention Deficit Hyperactivity Disorder,* is indeed real. It is a complex condition with variable symptoms. The American Psychiatric Association (2000) estimates that 3–5 percent of kids have it. The biological basis is becoming better understood, but is still not completely clear. Fortunately, it is treatable, and the treatments that you have no doubt heard about—stimulant medications—are effective for most children. Unfortunately, there is not much evidence that purely behavioral or talk therapies are as effective as medications. In this column, I'll tell you some of the basics about ADHD, and I'll describe what role you as a teacher have in helping a child with ADHD get the most out of school.

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ADHD is a real disorder, despite seemingly widespread beliefs to the contrary. I have met more than one person who snorts with disgust when ADHD is mentioned, saying something like, "In my day, if a kid had too much energy, you told him to run around on the playground for a while. Now they give him drugs!" Other doubters suggest that there are probably more kids with attention problems these days, but it's because this generation is easily bored due to excess television viewing and permissive parents who buy them too many toys. To make matters worse, ADHD's high incidence now (compared to its apparent absence a generation ago) gives the diagnosis a faddish feeling.

But all of these impressions are based on inaccuracies. ADHD is not new—it has been identified since the early 20th century. Until 1980, ADHD went by other names such as "restlessness syndrome" or "hyperkinetic impulse disorder." Sophisticated studies tell us that it is not caused by bad parenting, too much television, or playing video games. A large number of studies have examined the relationship of these sorts of social practices and found that they do not cause ADHD (e.g. Anderson, 1996). And further, there does not appear to be anything about American culture in particular that breeds the disorder; research demonstrates that ADHD exists in about the same percentage of children in other cultures (Szatmari, 1992).

What Is ADHD?

ADHD is a medical disorder for which there is very strong scientific evidence. It has three recognized subtypes, predominantly Hyperactive, predominantly Inattentive, and Combined, each of which looks a little different. Kids whose ADHD is predominantly Hyperactive-Impulsive, show mostly hyperactive and impulsive symptoms, i.e., they seem to fidget nonstop, they have a hard time playing quietly, and they don't seem to think before they act. Those with predominantly Inattentive ADHD show more inattentive symptoms, i.e., they don't seem to listen, they often seem to be daydreaming, and they have trouble organizing tasks. The third group, with Combined ADHD, shows both types of symptoms.

Interestingly, children with ADHD (regardless of subtype) can sustain attention when they find something in the environment of interest, for example a video game or movie, or a building project. The problem comes in controlling their attention; that is, directing and maintaining it when the object itself does not have properties that maintain the child's interest.

Researchers have a fair idea about at least some of what goes wrong in the brain of a child suffering from ADHD. A brain circuit is affected that involves structures near the center of the brain called the basal ganglia, and part of the prefrontal cortex—the front part of the outer covering of the brain. Brain imaging studies show that these structures are smaller and less active in ADHD sufferers than in non-ADHD control participants (i.e., Giedd et al., 1996; Zametkin et al., 1990). We also know that there are particular problems in the way these brain structures use dopamine, one of the chemicals that nerve cells in the brain use to communicate with one another and that play a crucial role in the basal ganglia and prefrontal cortex.

That's the biology behind ADHD. But what causes these biological differences? Geneticists have shown that ADHD is one of the most heritable psychiatric diseases known. Heritabilty refers to the extent to which one's genetic inheritance influences an outcome (i.e., the likelihood of developing ADHD). Some important studies of heritability have examined twins. Of course, twins can be identical (and so share 100 percent of their genes) or fraternal (and so share 50 percent of their genes). Studies show that if one twin has ADHD, then the other is much more likely to have it if the twins are identical than if they are fraternal. Note that the home lives of either identical or fraternal twins are likely to be quite similar (Levy et al., 1997). Thus it is the greater shared genetic component that drives the effect. Further, geneticists have identified several candidate genes that may be the culprit, most of which are implicated in the regulation of dopamine (e.g., Faraone et al., 1997).

How large is the genetic contribution? One way to think about it is to compare the effect of genetics on height and on ADHD: The heritability of ADHD is about 80 percent; the heritability of adult height is about 90 percent. In short, whether or not a child develops ADHD depends largely on his or her genetic inheritance, not the amount of television watched or a particular parenting style.§

This description of the brain basis of ADHD makes it sound as though kids won't just "grow out of it," and indeed, they don't. Kids with ADHD for the most part, but not uniformly, grow up to be adults with ADHD. And as they grow, these kids, if untreated, are at significantly increased risk for a host of problems (Barkley, 1998). They are much more likely than other kids to drop out of school and to have few or no friends. They are also at increased risk for teen pregnancy, drug abuse, clinical depression, and personality disorders.


It is not currently possible to diagnose ADHD via genetic testing (as we can, for example, for Huntington's disease) or by an analysis of the brain's chemicals. Rather, it is diagnosed via a careful analysis of behavior. A child must show six of nine symptoms in one of the two lists shown below to be diagnosed as either predominantly Inattentive or predominantly Hyperactive-Impulsive. If the child has six or more characteristics from both lists, he or she is diagnosed as Combined. These characteristics are evaluated relative to the child's peer group. Further, the symptoms must be present for at least a year, they must occur in at least two different settings, they must appear before age 7 (a rule that acknowledges ADHD's biological basis in the brain, which means the disorder would likely appear by age 7), and they must be severe enough that the child is impaired in major life activities, such as school work or getting along with friends (i.e., the symptoms actually cause problems). Together, these constraints work to protect against unmerited diagnoses. In addition, other possible causes of the symptoms must also be ruled out, e.g., other neurological or psychiatric disorders, a reaction to a stressor such as a chaotic home life, and so on. It may seem suspicious to you that there is not a 100 percent accurate marker for the disorder. But other diseases—for example, Alzheimer's disease—are likewise diagnosed via a set of symptoms coupled with exclusion criteria.

ADHD Symptom List
Inattentive symptoms Hyperactive/Impulsive
Failure to give close
attention to details; prone to
careless mistakes
Tendency to fidget and
squirm when seated
Difficulty sustaining attention and in persisting with tasks until they are complete Tendency not to remain seated when it is expected to do so
Often appears as if his or her mind is elsewhere Engages in excessive running or climbing where it is inappropriate
Frequent shifts from one uncompleted activity to another Difficulty playing quietly
Difficulty organizing tasks
and activities
Appears to be often "on the go" or "driven by a motor"
Dislike and avoidance of activities that require sustained mental effort Talks excessively
Disorganized work habits; materials necessary for tasks are scattered, lost, or
carelessly handled
Difficulty delaying responses; tendency to blurt out answers before a question is completely stated
Easily distracted by irrelevant stimuli; frequently interrupts tasks to attend to trivial events easily ignored by others Difficulty waiting one's turn
Forgetful in daily activities, e.g., misses appointments Frequently interrupting or
intruding on others
Brief description of the symptoms of ADHD. A more complete
description is available in the Diagnostic and Statistical
Manual of the American Psychiatric Association.


Ever since ADHD became a hot topic in the media, there has been much public discussion of overdiagnosis. It would seem that if you define "inattentive" relative to an age group, you are guaranteeing that the least attentive kids have a "disorder." But the criteria for diagnosis—for example, that the inattention must be causing a real problem for the child—are supposed to protect against that danger. Still, when a disorder gets a lot of press, it is possible that it is so much in the forefront of physicians' minds that it will be overdiagnosed. Researchers have investigated this possibility, and the data are mixed (e.g., Jensen et al., 1999; LeFever et al., 1999). Thus, an appropriately cautious attitude would indicate that ADHD may be overdiagnosed. But, we should also bear in mind that it may well be underdiagnosed in communities with poor access to healthcare.



The best known and most comprehensive study on treating children with ADHD was sponsored by the National Institute of Mental Health (NIMH). Eighteen well-known researchers at six medical research centers participated, and nearly 600 children, aged 7–9, were assigned randomly to be treated with (1) medication alone; (2) psychological/behavioral treatment alone; (3) both therapies combined; or (4) routine community care alone. The first results were published in 1999, and the study is ongoing. Results thus far indicate that either medication alone or combined treatment are more effective than behavioral therapy or community care alone in reducing ADHD symptoms. Other analyses indicated that these conclusions hold across race, ethnicity, and gender (Arnold et al., 2003). A recent follow-up study (MTA Cooperative Group, 2004) tracked the original participants and found that subjects who stopped taking medication had a return of ADHD symptoms, but those who had continued their medication did not. Further, those who had not taken medication as part of the study, but then began taking it when the study ended, showed a reduction of ADHD symptoms.

This research concerned the reduction of symptoms, which doesn't guarantee improvement in more complex behaviors like performing well in school or getting along with peers. When these more complex behaviors were measured, the NIMH study indicated that the combined treatment of medication and psychological/behavioral treatment held a slight edge over either treatment on its own. But other recently published work came to the conclusion that training in social and academic skills combined with medication provided no advantage to children over and above medication alone (Abikoff et al., 2004; Hechtman et al., 2004).

Still other behaviors of concern are the risk factors mentioned earlier, such as increased risk of substance abuse, antisocial behavior, and so on. These risks are meliorated by medication (e.g., Abikoff et al., 2004; Klein et al., 1997; Wilens, 2004). This protective effect is not an inoculation, however. The meliorating effect lasts only as long as the child is taking the medication. Obviously, different risks are associated with different ages, depending on the time of life. A 6-year old will not be at risk for dropping out of school, whereas a 16-year old might be. One might, in particular, think that medicating children with stimulants would put them at greater risk for abuse of stimulants (or other drugs) later in life. That appears not to be the case (Mannuzza, Klein, and Moulton, 2003).

It is fair to ask whether these children really need medication. Most children (and adults) don't like to pay attention to things that are not inherently interesting. Many overcome this dislike, and we attribute their ability to stick with a task as a sign of good character; their behavior shows perseverance and diligence. Couldn't kids with ADHD overcome their problem with some gumption? Are we perhaps depriving children with ADHD of the opportunity to develop strong character if we provide medication? Character is doubtless important, but children with ADHD are not just fighting a disinclination to do uninteresting work the way others do—they are fighting their physiology. It's rather like asking a child with limbs weakened by polio to do ten pushups, just as everyone else does. Greater perseverance will help that polio-impaired child, but even great perseverance won't bring him or her to the athletic level that a normal child could reach with far less effort. Likewise, strong character is not unimportant for the ADHD child, but without medication, his strong character simply won't be able to produce as much concentration and focus as could the non-ADHD child with less strength of character and less effort.

What are we to conclude from these data? Obviously, there is solid evidence that medication is effective, and there is less evidence that behavioral or psychological treatments work as well. But we should not conclude that these latter treatments should be abandoned. There is variability among children. Some don't respond to medication or cannot tolerate it due to side effects. Some show better response to behavioral interventions than others. It should also be borne in mind that across different studies, the behavioral treatments will vary in their design and in how effectively they were implemented. There are also differences among kids in what their home and school environments are like without these interventions—some parents and teachers already provide a fairly structured, predictable world, whereas others do not. The behavioral intervention would make a much bigger difference to a child in the latter situation.

Another feature of these studies is noteworthy. Medication was effective, but the children were very closely monitored in terms of their responses to different doses, presence of side effects, and so on. Everyone who advocates medication for kids with ADHD must also advocate very close monitoring of its effects.

What if you suspect a student in your class has ADHD?

Suppose there is a child in your class who seems to have many of the symptoms listed in the chart above. What should you do? Obviously, as a teacher you are not trained to make a diagnosis, and even if you were, you only see the child at school and a positive diagnosis requires observation in at least two settings. Nevertheless, as a teacher you are in a position to observe the child for extended periods, and you have a good idea of appropriate behavior for the age group. Your knowledge and opinion is critically important. Each school should have a clear, known process through which your concerns can be addressed. Typically, the school principal would have a designee, usually a guidance counselor or psychologist, who is authorized to convene a meeting of various school personnel to consider the evidence and, if merited, recommend a formal ADHD evaluation. If you suspect a child may have ADHD—meaning you see multiple symptoms for several months—don't keep it to yourself. Bring the issue to your principal or the designated staff person in your school. Bear in mind that if this child does have ADHD, he or she is at significant risk to develop further problems—and that risk can be attenuated with treatment.

What if a child in your class has diagnosed ADHD?

Suppose instead that you have a child who has been diagnosed with ADHD in your classroom. What can you do to help him or her get the most out of school? Again, the first thing to keep in mind is that you must coordinate with others. Your school counselor or psychologist should be helpful in coordinating your efforts with those of the child's parents and physician. Obviously, it is vital that any changes you make in your classroom are supported by changes made in the child's home and vice versa. Here is a list of the sort of changes that might be suggested to you (for further reading, see Barkley, 1998):

Make it easier for the child to pay attention

Subtle changes to the environment may help the child with ADHD focus attention. Sitting close to you may help him or her maintain attention on class work. If your desks are arranged in circles or clusters, make sure that the child is oriented so that he or she can see you most of the time. ADHD kids may also frequently seem not to listen, even when directly addressed. Try using the child's name any time you directly address him or her.

Immediate and frequent consequences

Kids with predominantly impulsive ADHD don't think about the consequences of what they are doing before they do it. Making the consequences immediate may help them to make that connection. For example, a child may be told to play alone for a few minutes if he grabs a ball from another child during recess. Positive consequences should follow positive behaviors, as well. The child should be rewarded or praised when he politely asks to share the ball instead of grabbing it.

Break tasks into smaller chunks

Because kids with ADHD have trouble focusing attention and trouble staying organized, you may be asked to make tasks shorter and more manageable for them. For example, rather than telling a high school sophomore to write an essay on the causes of the American Revolution, the teacher may provide a series of steps for the student: find relevant research materials; read and summarize the materials; write a brief outline; expand the outline with more details; write a rough draft; edit the rough draft. The teacher would evaluate the work at each stage and provide immediate feedback. The teacher thus takes over from the child some of the requirements for organization and self-regulation.

Use prompts, especially for rules and time intervals

Students with ADHD have a special problem with regulating their own activities and so will benefit from prompts or reminders. For example, other children may readily learn the rule that students must take a hall pass to go to the bathroom and that it must be replaced on the hook when they return. The child with ADHD will likely need to be reminded of this rule many more times than other kids. Another aspect of regulating one's own behavior is anticipating how long it will take to complete an ongoing task and allocating effort on the different stages of the task accordingly. Again, the child with ADHD will benefit from prompts about time, e.g., "Everyone has five more minutes to complete their graph, so you should be about halfway done by now."

Artificial rewards

Sometimes a child responds very well to a reward system, such as a token economy. The child might earn points or plastic coins for each instance of appropriate behavior (e.g., a class period in which he doesn't get out of his seat). These artificial rewards can later be exchanged for a desirable toy or other tangible reward. The goal in such programs is not to "buy" appropriate behavior, but rather to shape behavior toward the target so that the rewards can be reduced in frequency and eventually discontinued, with the desirable behavior remaining.

Contact with parents

You will likely be asked to be in frequent touch with the child's parents in order to update them on his or her progress, alert them to any problems that arise, and so on. Sometimes a daily "report card" is used, which briefly summarizes the child's progress on targeted behaviors.

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You'll note that many of these suggestions are rooted in the idea of putting more regulation for the child in the environment since the child is not able to regulate himself or herself very well. Another goal is to make the environment more predictable; if the child knows what's coming, he or she may more easily learn to self regulate.

As much as ADHD is disruptive to a child's academic performance, the possible long-range consequences of the disorder are still more dire: academic failure, social isolation, and increased risk of drug abuse and other self-destructive behaviors. Early intervention is the child's best hope, and teachers have an important role to play in triggering and providing this intervention.

Daniel T. Willingham is professor of cognitive psychology and neuroscience at the University of Virginia and author of Cognition: The Thinking Animal. His research focuses on the role of consciousness in learning.

*The term Attention Deficit Disorder (ADD) is no longer used. (back to article)

Although adults do suffer from ADHD, I will refer throughout this article to people with ADHD as though they are children, since we are focused on K–12 students. (back to article)

Of course, we expect that younger children will be more distractible than older children and will have a harder time knowing when it's appropriate to play quietly and when they can burn off energy. That is why a diagnosis of ADHD requires that symptoms be evaluated relative to same-age children. (back to article)

§A recent report that kids who watch a lot of television at ages 1 to 3 tend to develop ADHD by age 7 (Christakis et al., 2004) got a lot of press attention, but that study was rife with problems. Two of the more important problems were that no one in the study was clinically evaluated for ADHD (parents reported on a few categories as to whether their children had attentional problems) and the study showed a correlation of these reported attention problems and watching television, from which one cannot conclude that watching television causes attention problems. It is perfectly plausible that kids with nascent attentional problems like to watch TV more than kids who will not later develop attention problems. (back to article)


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American Educator, Winter 2004-2005