Professor of psychiatry and neurology at the University of Massachusetts Medical Center in Worcester. Author of numerous books on ADHD, including ADHD and the Nature of Self-Control and Attention- Deficit Hyperactivity Disorder: A Handbook for Diagnosis and Treatment.

I've been involved in doing research since 1973. I've been a licensed psychologist since 1977, but I've devoted my entire scientific career to studying children with ADHD. Over that period of time, I've seen several things in the field. Most importantly, the way we think about the disorder and conceptualize it has changed markedly.

Back in the 1950s and 1960s, we really thought . . . that these were children who moved around a lot and climbed on furniture and couldn't control their activity level, and we called them hyperactive children. We then learned in the 1970s and the 1980s that they had tremendous problems with inhibitions, with impulse control. They can't stop and think before they act. They say things without regard to what's going to happen to them for saying or doing those things. We also found they had tremendous problems with being distractible and inattentive. So our view of the disorder expanded greatly over that period of time.

It's now evolved to a point where we have begun to see ADHD as a deeper problem with how children develop self-regulation and self-control. These problems with activity level, and later, with attention span and with impulse control, are simply the more superficial manifestations of a deeper developmental disorder, and with how the children go on to develop self-regulation--the ability to control your own behavior for social purposes.

We've also changed our understanding of the etiology of ADHD. . . . Back in the 1950s and 1960s, we didn't know what caused it. There was a suspicion that maybe bad parenting or social learning of some kind attributed to it. Other people thought it was just an immature personality development, and that within a few years, these children would outgrow the problem by the time they were adolescents.

We know now, thanks to a number of studies over the last decade, that ADHD is a real developmental disorder; that largely biological and genetics contribute to the disorder; and that it's the most inherited of all the psychiatric disorders, rivaled only by autism in terms of its genetic contribution to it. And we're beginning to focus now on three critical brain structures that seem to be implicated in this disorder. Interestingly enough, they are the same brain structures that are involved in inhibitions and in developing self-regulation--the ability to stop and think before you engage in your behavior.

Your conception of self-control varies from others' views. Why have you chosen self-control?

Well, I've begun to study self-control in ADHD children, because we began to realize that the problems with attention that ADHD children were having were not problems with how they perceived things or see the world around them. It really was more of a problem that they couldn't persist at something as long as other people. And they couldn't resist the distractions around them as well as other people, particularly when they were involved in very boring or very tedious work.

That began to suggest that there was a problem in how they were controlling behavior, not in how they were seeing the world. It would therefore be a problem with how the output of the brain--behavior--is organized, and not a problem with input coming into the brain, with how you perceive and see your world. . . .

What we've found is that ADHD children can pay attention to things that are around them in the immediate situation, so that it's really not an attention problem. What they don't pay attention to is what lies ahead in time, what has to be done next in order to get ready for the future. They're not stopping to think about that future. So they don't have a problem with attention; they have a problem with intentions. Intentions are the things we are doing to get ready for what lies ahead in time--our goals; our plans; the assignments that we should be working on; the paths that other people have given us that we need to be paying more attention to in order to be ready when that time gets here. That's what ADHD children are not doing. . . .

Are there studies that indicate an element of the brain that might be different?

We think that the brain is very much involved in ADHD, for a number of good reasons. First of all, for many years, an extensive amount of research shows that the kinds of electrical activity that we can monitor . . . indicates that certain portions of the brain, particularly the right frontal area, are less active, less mature. They're under-aroused more than they should be, and we've known this for a long time. Other studies, also using brain electrical activity, indicate that the brain doesn't respond as quickly to certain kinds of stimulation, particularly stimulus to stop and inhibit their behavior. And so we have a large amount of research there as well.

More recent studies using blood flow have indicated that these critical regions in the brain that I'm referring to are less active than they should be, and aren't calling for as much blood as they ought to in order to keep themselves activated. More recently we've used magnetic resonance imaging (MRI) technology, to image the brain. And several studies now indicate that these structures are less developed, less mature. They're smaller in people with ADHD than they ought to be.

Finally, using the most recent technology called "functional MRI," studies are now indicating that these brain regions are substantially less active than they ought to be for someone of that age group. So we have multiple lines of information that converge on a common conclusion: that we have three regions in the brain that are less developed, less active than they should be; and, it turns out, that these regions are absolutely crucial for inhibitions and for thinking before you act--for self-control.

So this is a biological disorder.

It's largely a biological disorder. It has many causes, but all of the known causes fall within the realm of neurology and genetics. We can rule out the social environment, such as bad parenting, intolerant teachers, the breakdown of the American family, a decline in family values, excess amount of TV viewing or video games. These have all been proposed as causes of ADHD. But there's no evidence that we can find that will substantiate them.

All of the evidence that keeps turning up in our research points to genetics and neurology as being largely responsible for the excessive behavior and the poor self-control that we see in these children. So I think we can safely say that what we've learned in the past ten years is that environmental causes of ADHD are not credible. They do not account for the substantial amount of scientific findings that exist on this disorder today.

Is this a mental illness?

Well, it depends on how you want to define a mental illness. I prefer to call it a developmental disability, because, like mental retardation, like the learning disabilities such as dyslexia and autism, it comes on very early. It appears to be a problem with the way the brain is developing. It affects the child's life in many different capacities, and it has long-term consequences for the individual. So, in that sense, it's very much like the other developmental disabilities that we know so much about.

It is classified as a mental illness by the American Psychiatric Association, and it is placed in their manual of mental disorders as such. But that's just a matter of classification. I think more scientists view it really as being akin to the developmental disabilities, rather than being more like schizophrenia or bipolar disorder, where there's some, perhaps, gross abnormality in the individual's development. Here, instead, what we're seeing is an immaturity and a failure to develop as quickly as other people in these critical areas of personality development and self-control.

A lot of people--such as parents--feel very uncomfortable with the label. Is it important to label it?

Well, labeling is a two-edged sword. Of course, it brings with it all the negative connotations. You're being singled out; you'll be stigmatized. It is a label that is mentioned in psychiatric textbooks as a mental disorder, and, of course, people are afraid of stigmatizing their children so young in life with the label of a mental disorder. But on the other hand, there is the upside to labeling, an upside that we can't avoid, and that's why we continue to use labels.

First of all, by using a precise label, we can connect this group of individuals up with a large body of scientific knowledge about other people with this label and with this disorder. So if we use this label, it brings with it a tremendous amount of information that can help the individual better understand their disorder and how best to manage it. If we start labeling it with some euphemism, some ambiguous personality term like, they're just "high-energy children," you've disconnected immediately from this larger body of accurate scientific knowledge that we have. And that's a disservice to these people.

The other disservice it will do is that there are rights, protections and access to services that people with ADHD have a right to now because of various legislation that has been passed to protect them. There are special education laws. And the Americans with Disabilities Act, for example, mentions ADHD as being an eligible condition. If you change the label, and again refer to it as just some variation in normal temperament, these people will lose access to these services, and will lose these hard-won protections that keep them from being discriminated against. . . .

There are 6,000 studies, hundreds of double-blind studies, and yet, there's still controversy. Why?

There is controversy about ADHD, I believe, partly because we are using a medication to treat the disorder, and people find that to be of concern. But there's also concern because ADHD is a disorder that appears to violate a very deeply held assumption that laypeople have about children's behavior. All of us were brought up believing, almost unconsciously, that children's misbehavior is largely due to the way they're raised by their parents and the way they're educated by their teachers. If you wind up with a child who is out of control and disruptive and not obeying, that that has to be a problem with child rearing.

We can thank Freudian thinking and Watson's behaviorism, and other ideas that are part of our common knowledge, for making us believe that behavior problems are learned. Well, along comes this disorder that produces tremendous disruption in children's behavior, but it has nothing to do with learning, and it isn't the result of bad parenting. And therefore it violates these very deeply held ideas about bad children and their misbehavior.

And as long as you have this conflict between science telling you that the disorder is largely genetic and biological, and the public believing that it arises from social causes, you're going to continue to have tremendous controversy in the mind of the public.

Now, there is no controversy among practicing scientists who have devoted their careers to this disorder. No scientific meetings mention any controversies about the disorder, about its validity as a disorder, about the usefulness of using stimulant medications like Ritalin for it. There simply is no controversy. The science speaks for itself. And the science is overwhelming that the answer to these questions is in the affirmative: it's a real disorder; it's valid; and it can be managed, in many cases, by using stimulant medication in combination with other treatments.

There are studies, like the NIH consensus report, that question the diagnosis. A panel of experts concluded that we know something, but not everything.

Let me point out two things. The consensus conference that was held earlier and sponsored by a number of organizations, including NIMH, was a reasonable idea. But it was seriously flawed from the start, and you have to keep these flaws in mind in understanding this document.

First of all, it was a political activity, not a scientific activity. The experts that were chosen to review the literature are not experts in ADHD. They are practicing professionals in other fields of science, or are simply clinical practitioners. They are certain not experts in ADHD. Experts, people like myself and others, were called to present our information to the panel. But the panel itself was not a body of experts, and it shouldn't be misrepresented as such. That also leads to problems, because you have people who don't know the literature trying to understand what the science has to say within just a few days.

. . . Because it was a political document, it also had to include phrasing that was a bit of a bone to the critics of ADHD, tossing them a certain kind of sentence here and there so that they wouldn't feel misrepresented in the panel discussions. But many scientists would not have put those phrases in there, because they make it sound like we know less than we really do about this disorder.

For instance, saying that we're not sure about the safety and the long-term use of the stimulant medication is nice to say. But the fact is that we know more about the stimulant medications than just about any other medication that's given to children in medicine. . . . All of the research we have indicates that these drugs are some of the safest that we employ in the field of psychiatry and psychology. That's not to say that we know everything about them. But we know a lot more than we know about cough medicines and Tylenol and aspirins and other things that children swill whenever they come down with a common cold. Nobody asks those questions about those over-the-counter medications, yet we know substantially less about them.

So I think that the consensus document was flawed in a number of ways, and largely, it has to be viewed as a political document, not as a series of scientific conclusions drawn up by experts who specialize in this field. You would have had a very different document if you had asked the experts to write it.

As a psychologist, how do you view this issue of the effectiveness of behavioral modifications and medicines?

There's supposed to be some controversy these days about the role of behavior modification and psychological treatments, versus the role of medication, in the management of ADHD children. I think that controversy stems from the fact that, the more we have studied these treatments, the more we have come to realize that, in head-to-head comparisons, medication appears to be more effective than behavioral interventions in managing the symptoms of the disorder itself. But the behavioral interventions appear to be useful in managing other disorders that are sometimes seen in conjunction with ADHD.

For instance, ADHD children, in over half the instances we see, are going to be very oppositional, very defiant, very difficult to manage. That's a second disorder known as oppositional disorder, and it's going to create a great deal of stress in the parent-child relationship in the home environment. We know that parent training and child management skills and behavior modification techniques can help with that kind of disorder, and with those kinds of parent-child relationship problems, even if it doesn't address the difficulties the child has with their symptoms of ADHD. . . .

But there's no question that, if you compare medication with behavioral interventions for the disorder itself, that the medication is always more effective than the behavioral interventions tend to be; which is why we continue to use it as much as we do. . . .

Is there over-medicating, or under-medicating?

The question that keeps being raised in the media now is whether there's over- or under-medication. We don't know for sure, because we don't have any national databases where we keep track of all prescriptions in the United States, like some other countries do. So we can't turn to that database to answer the question.

What we have to do is to go out and find large regional databases that are being kept. For instance, each state is required to keep records on all of the Schedule II drugs, like stimulants, that are being prescribed within their state. So we may be able to go to a state, as was done in the state of Maryland just recently, and look at the number of prescriptions being used for ADHD. We might get some indication there. We can also go to school districts and survey them and see what percentage of children is on medication. When we do this, we find a rather dramatic difference in figures that's difficult to reconcile.

If we go out to Utah where a survey was recently done, it's about 1.4 percent of children in the Salt Lake City public schools. If we go to five different metropolitan areas, as Peter Jensen did in one of his studies, we might find that the figure is around 1.8 percent to about 2.4 percent of ADHD children who are taking medication. In their own survey, the state of Maryland recently found that about 2.6 percent of children within the state were taking medication during school hours for management of ADHD. So it just depends on where you look.

If you were to average across all of these figures, it appears to be that somewhere between about 1.5 percent and about 2.5 percent of school-age children are taking medication right now for ADHD. Now, you have to look at that figure in the context of how much ADHD is there. It's the only way you can answer the question of over-medication, and that is, what's the reference point? We know that approximately 5 percent to 7 percent of school-age children have this disorder. If we use the conservative figure of 5 percent, and we know that about 2.5 percent of individuals may be taking medication, there's your answer. We don't have over-medication. Only about half of all ADHD children are ever taking medication for their disorder. . . .

Where were these kids when you were in elementary school? Suddenly this illness is everywhere.

Many people in the public ask, "Where were these kids when I was growing up? I've never heard of this before." Well, these kids were there. They were the class clowns. They were the juvenile delinquents. They were the school dropouts. They were the kids who quit school at 14 or 15 because they weren't doing well. But they were able to go to work on their parents' farm, or they were able to go out and get in a trade or get into the military early. So they were out there.

. . . Back then, we didn't have a professional label for them. We preferred to think of them more in moral terms. They were the lazy kids, the no-good kids, the dropouts, the delinquents, the lay-about ne'er-do-wells who were doing nothing with their life. Now we know better. Now we know that it is a real disability, that it is a valid condition, and that we shouldn't be judging them so critically from a moral stance. . . .

But there are people who ask, "Why medicate the class clown?"

Well, there are people who ask, "Why should we medicate these individuals? Why shouldn't we just allow them to go ahead and do what they're doing?" Well, it's because what they're doing is getting them into a great deal of difficulty. What they're doing is leading them into major impairments in serious life activities, so that they're not going to be doing very well in life.

For instance, we know that between 25 percent and 50 percent of ADHD children will be retained in a grade at least once. We know that 37 percent of them will never finish high school, despite special educational services and all the assistance we have available. We know that only 5 percent of these people will ever complete a college program, versus 35 percent of the normal population. We know that these individuals are more likely to have teenage pregnancies, to drift into delinquency, to experience drug abuse, to be under-employed, and to change their jobs more often.

My own research has demonstrated unequivocally that ADHD creates tremendous problems for operation of motor vehicles, for managing money, for handling day-to-day responsibilities. ADHD individuals, for instance, are four times more likely to be in a serious car accident because of their disorder than are other people. . . .

So, no, we're not going to go on letting them be the class clowns who wind up getting no high school education, who are under-employed in life, who drift into substance abuse, and who therefore are prone to more criminal activity. If that's what you're asking us to do, my profession's not going to stand by and let children suffer like that--not when we have treatments that are known to be effective, and that are some of the most well-studied treatments in psychiatry. It would be criminal for us to stand by and let that happen. . . .

Do you think there's consensus among psychiatrists and among their peers about how to treat and diagnose?

Yes, unquestionably. I would have to say that there is certainly a consensus about how ADHD ought to be managed. Most people in the scientific community and in the clinical practice community understand that ADHD has to be managed through the use of a combination of interventions, and we can reduce those to four things.

First, a proper evaluation that provides for a thorough diagnosis, so that we know that you have this disorder, and what other disorders you may have as well. Second, taking time to educate families about the disorder--what it is, what causes it--so that they can be better informed in raising these children, and not fall prey to some of these media stories that tend to scandalize the subject and misrepresent it so poorly. Third, the use of medication. What are the medications that are out there? What are the side effects, what are the real effects? So families can be educated about that, as well.

And then, combining that with behavior modification techniques, child management strategies, special educational services--what I call the accommodations--can be useful. And if you use those for intervention, as many professionals do, then you're doing the best we can for dealing with this disorder.

So diagnosis, education, medication, and accommodations are the standard, most useful, treatment package for this disorder. And most people try to do that within the limits of managed care and the other constraints that we see on medical and professional practice these days.

But those limitations have a big impact on people. Most people can't go to the best psychologist and go to a pediatrician for 15 minutes.

That's true. Many people say that professionals who diagnose ADHD may not be taking enough time to do a thorough evaluation of the disorder. And although that's true, we shouldn't use that to lampoon pediatrics or psychiatry as if it's their fault. What you have at play in the United States right now is a tremendous influence of managed care trying to keep the cost of medical services down, and in doing so, dictating to physicians what they can and cannot do in the course of their practice.

So it's managed care that's saying that a pediatrician only has 20 minutes to evaluate a child for this disorder. And it's managed care saying that, if the pediatrician wants to refer this child for a specialized evaluation by someone more expert in mental disorders, that they can't do that, because it's too costly, and only the more severe children are going to be allowed through the gate to see the experts.

So before we use this as a criticism of the professions, let's not forget that we're all struggling right now with these constraints that managed care is placing on access to services. And it's causing these very same kinds of problems that you raised. Children may not be getting as thorough an evaluation as they ought to; they may not be allowed to see experts in mental disorders as readily as they should; and therefore, they may not be given the most effective treatment package that we have available in this country. A serious problem in its own right is access to service, and that's a big problem right now for families with ADHD children. . . .

Skeptics say that there's no biological marker--that it is the one condition out there where there is no blood test, and that no one knows what causes it.

Well, people say that ADHD can't be real--that it can't be a valid disorder--because there's no lab measure for it. But that's tremendously naïve, and it shows a great deal of illiteracy about science and about the mental health professions. A disorder doesn't have to have a blood test to be valid. If that were the case, all mental disorders would be invalid--schizophrenia, manic depression, Tourette's Syndrome--all of these would be thrown out. They wouldn't be considered valid disorders; they'd all be fakes. There is no lab test for any mental disorder right now in our science. That doesn't make them invalid.

I might also point out, by the way, that there are no lab tests for all of all the disorders that we treat in medicine. There is no lab test for multiple sclerosis, for Alzheimer's disease, or for epilepsy. We may be able to use lab measures of them when they're in their most severe stages. But in their early stages, there are no lab measures. They're based on the same way we approach the diagnosis of ADHD. They're based on history, on your presenting complaints, how consistent those symptoms are with what we know about the disorder, and being able to rule out other possible explanations for your symptoms. And as long as we can do those things, we can come to the conclusion that you have this disorder and that it's a valid disorder.

I find these criticisms that there's no biological marker for the disorder to be a bit lame, quite frankly. They're actually kind of boring, because people really haven't gone to the library to do their research. If you're saying that we don't understand ADHD down to the level of molecules and cells and proteins within the brain, well, that's true. But that's true of many disorders in medicine and in all of psychology. But they're still valid disorders. . . .

How do the medications work?

Stimulants seem to work by increasing activity within certain brain regions. By increasing or stimulating these brain regions, they result in greater powers of inhibition. The individual is able to stop and is able to engage their processes before they act. . . . What the stimulants do is to activate these critical brain regions that are involved in inhibition.

Now, as far as what they're doing at the level of chemistry and proteins, we're not quite sure yet. We do have some indications that the stimulants are achieving an increase in the amount of dopamine that is within the synapses between brain cells--those critical gaps between the brain cells where the neurotransmitters are supposed to do their job. Evidence indicates that drugs like Ritalin slow up how much of that chemical is being reabsorbed into the nerve cell, so that more is left in the synapse. Other medications, like Dexedrine, may just increase the production of dopamine within these nerve cells.

However they do it, the stimulants all have in common that more dopamine seems to be available within these critical brain regions to allow them to be more active, and to do the job of inhibiting behavior that they're supposed to do.

Why are these drugs compared to cocaine?

The drugs are compared to cocaine because chemically, they are similar to cocaine. That doesn't mean that they act like cocaine. For a drug to be similar doesn't mean that it's identical or that it does the exact same things that cocaine happens to do. Many critics of the stimulants have badly misled the public into thinking that, because the drug is chemically similar, it is identical--and that's misleading. What makes a drug like cocaine addictive is how quickly it enters and clears the brain. Cocaine, because it is inhaled through the sinus passages, is rapidly absorbed into the bloodstream and taken immediately into the brain. There is a rapid change in consciousness. And it's that rapid change in consciousness that humans perceive as addictive, as so seductive to them.

On the other hand, drugs like Ritalin and the other stimulants are taken orally. They're absorbed very gradually through the intestine. They enter the bloodstream in very slow, gradual amounts. Therefore, they're entering and leaving the brain in a very controlled and subdued fashion. As a result, they are not addictive whatsoever when they are taken orally. All of the evidence points to these being non-addictive drugs when taken as prescribed.

Of course, if you were to crush a tablet of a stimulant medication and inhale it, you might well become psychologically dependent, and possibly even addicted to inhaling this medication. But, of course, you can do that with airplane glue and paint thinner and gasoline. But I don't see anybody requiring these being prescribed monthly the way we control access to the stimulants. Any drug can be abused if you administer it through a different route than the way it's intended to be used. But, used as prescribed, the stimulants are not addictive.

So you don't believe they should be classified as Schedule II?

. . . I've taken a position that they should be removed from the Schedule II controlled substances and allowed to be Schedule III drugs--where you don't have to go to a physician every month to get a new prescription, and they can be used like other psychiatric drugs--you can be given multiple prescriptions that you can renew. But I understand why some people might be a bit concerned about that, and not because the drugs are being abused by a large percentage of people or because they are addictive.

The concern arises about the potential for abuse--if you allow the drugs to be prescribed more easily, would they be abused more by the general population than they are now? That's an empirical question. We haven't tried that experiment to see whether or not our concerns are well founded. I happen to believe that the convenience that would come to families of ADHD children and the lowering of medical costs that would come with rescheduling these drugs into the non-addictive category would outweigh the abuse potential that some people think might be there. . . .

These meds are performance-enhancers. Are they also life-enhancing?

Well, many medications can be considered life-enhancing or performance-enhancing medications. Prozac, for instance, when it first came on the market, was criticized, because people were taking it to fine-tune some of the edges of their personality when they really didn't have major depression. And undoubtedly some people are taking stimulant medications, not because they have ADHD, but because they want to stay up and get more work done; or they're truck drivers who want to be driving longer hours without sleep than they ought to be; or they're people like Bob Fosse, the choreographer, who was so involved in his profession and didn't sleep much and was taking stimulants in order to be a more productive individual.

There are certainly people who can misuse the stimulants as performance enhancers. But the fact is that the largest percentage of prescriptions for the stimulant medication are being prescribed for the disorder, for a valid condition, and are being prescribed appropriately. There's always going to be a certain small percentage of the public who wants to try a medication to tweak their personality a little bit, to see if it makes them more competitive in this competitive environment that we live in. I don't think you're going to be able to stop that. But that's no reason to keep people with a legitimate mental disorder from having access to treatments that are well established and that are safe and effective for them.