Is attention deficit hyperactivity disorder (ADHD) a legitimate diagnosis or is it mostly a fraud? The answer has important implications for many individuals and for society. The diagnosis is accepted as legitimate by the psychiatric profession, but continues to have its vehement critics. Recently, noted psychologist Jerome Kagan has been giving tremendous weight to these criticisms by calling ADHD mostly a fraud. There are significant problems with his criticism, however.

What is ADHD?

ADHD was first described in children in 1902, and was understood as an impulse control disorder. It was not formally recognized as a diagnosis, however, until the second edition of the DSM in 1968. The first approved drug used to treat ADHD was benzedrine in 1936. Ritalin, which is still used to treat the disorder, was approved in 1955.

Here is the official DSM diagnosis:

  • A persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development
    • Six or more of the symptoms have persisted for at least six months to a degree that is inconsistent with developmental level and that negatively impacts directly on social and academic/occupational activities. Please note: The symptoms are not solely a manifestation of oppositional behaviour, defiance, hostility, or failure to understand tasks or instructions. For older adolescents and adults (age 17 and older), five or more symptoms are required
  • Several inattentive or hyperactive-impulsive symptoms were present prior to age 12 years
  • Several inattentive or hyperactive-impulsive symptoms are present in two or more settings (e.g. at home, school, or work; with friends or relatives; in other activities)
  • There is clear evidence that the symptoms interfere with, or reduce the quality of, social, academic or occupational functioning
  • The symptoms do not occur exclusively during the course of schizophrenia or another psychotic disorder and are not better explained by another mental disorder (e.g. mood disorder, anxiety disorder, dissociative disorder, personality disorder, substance intoxication or withdrawal)

There are a few aspects of this diagnosis worth pointing out. First, this is what we call a clinical diagnosis, it is based entirely on signs and symptoms without any objective diagnostic tests. You cannot see ADHD on an MRI scan of the brain, an EEG, or a blood test. This is not unusual in medicine, especially for brain disorders. The same is true, for example, of migraine headaches. It is entirely a clinical diagnosis.

This, by itself, should not call the diagnosis into question. Brain function relies not only on the health of the cells and the absence of identifiable anatomical or gross pathology. It also depends on the pattern of connections among brain cells, the density of their connections, and the details of their biochemistry. We are just starting to be able to image the brain at this level.

As an example, raise someone in a closet for 20 years and I guarantee you they will have a psychological disorder, but you would not be able to tell that from looking at their brain with any tool we currently have.

Because mood, thought, and behavior largely rely on brain function that cannot be imaged, psychiatrists have relied on elaborate schemes of clinical diagnoses to at least have a common language for thinking and talking about mental illness. It is imperfect, and extremely fuzzy around the edges, but it has its utility.

That fuzziness is partly based in the limits of our current technology and understanding. But it is also based in the fact that humans are neurologically heterogeneous and the fact that the brain is an extremely complex system. This means that the same end result (behavior, for example) might result from almost endless permutations of interactions among various systems in the brain and their interaction with the environment.

You can see this in the formal description of ADHD above. There is a sincere attempt to capture a real neurological phenomenon, and to filter out other factors that might contribute to or cause similar symptoms. Signs used to establish the diagnosis cannot be temporary, or isolated to only one environment, or related to other conditions or situations that might provoke them. You need to have many symptoms persistent over a long time without other identifiable causes and to a sufficient degree that they cause demonstrable harm.

There is also an attempt to separate out those who have a real disorder from the typical spectrum of human behavior. This is also a common problem in medicine. Many disorders, like high blood pressure, do not have a sharp demarcation line. The curves for normal blood pressure and hypertension overlap. Experts have to decide where to draw the line, either capturing more people with the disorder but also more people just at the upper range of normal, vs excluding those who are just at the upper range of normal but also then missing more people with the disorder.

Eventually such clinical questions evolve from, “Who has the disorder” to “Who benefits from treatment for the disorder.” That is the real question.

Neuroanatomical Correlates

Despite the fact that ADHD is a fuzzy clinical entity, we have made progress in understanding what is happening in the brain of most people with ADHD. The current consensus is that ADHD is a deficit of executive functions. The frontal lobes carry out many critical functions, some considered executive functions: they include being able to focus your attention, maintain focus, switch among tasks, filter out distractions, and impulse control. Executive function includes the ability to weigh the probable outcomes of your behavior and then make high-level decisions about how you will behave.

As an adult neurologist I see patients with executive function disorder frequently, usually from head trauma. Car accidents in particular result in frontal lobe damage as it is common to hit your head against the windshield during many types of accidents. Patients frequently develop the symptoms of ADHD after frontal head trauma. They have poor focus, and poor impulse control. In one dramatic case a patient’s entire personality changed. She lost all ability to control or moderate her behavior (as have others). Often these patients respond favorably to the same stimulants we use to treat ADHD.

When we look at the brains of those who meet the clinical diagnosis of ADHD with our modern imaging techniques, such as fMRI and EEG, we find a similar pattern of brain dysfunction:

Convergent data from neuroimaging, neuropsychology, genetics and neurochemical studies consistently point to the involvement of the frontostriatal network as a likely contributor to the pathophysiology of ADHD. This network involves the lateral prefrontal cortex, the dorsal anterior cingulate cortex, the caudate nucleus and putamen. Moreover, a growing literature demonstrates abnormalities affecting other cortical regions and the cerebellum.

At this point there is no reasonable disagreement about the fact that ADHD is a disorder of brain function. Children who meet the strict diagnostic criteria are demonstrably different, in consistent and predictable ways, than children who do not (controlling for other possible factors). They have impaired executive functions, and we can see this in changes to the relevant parts of the brain. We still have a lot to learn (again, the brain is complex) but a consistent picture is emerging.

Jerome Kagan’s criticism

Jerome Kagan is a preeminent psychologist. This gives his opinions about a psychological topic a great deal of weight. The press loves him because he has a sensational story to tell and he has impeccable credential. Articles about Kagan often spend an entire paragraph or two touting those credentials.

Unfortunately this is a common mistake that mainstream journalists make when discussing scientific topics. They confuse the expertise of an individual with scientific authority. No individual ever represents the consensus of scientific opinion, they can only represent their own quirky opinions (which may or may not be in line with the consensus).

This is a classic example of this error. Kagan’s opinions do not conform to the current consensus of scientific opinion, but he is presented as an unimpeachable authority. Further, all reporting that I have seen on Kagan’s opinions regarding ADHD fail to put his expertise into a reasonable context. Kagan is a psychologist. He is not a psychiatrist, nor a neuroscientist.

Often related fields covering the same question have different opinions. Geologists and paleontologists disagree about the relative contribution of a meteor impact to the extinction of the dinosaurs at the K-Pg boundary. If a reporter talked only to a geologist they would not capture the true state of the broader scientific opinion.

Many psychologists have opinions about psychiatry that do not reflect the consensus of psychiatric opinion. In essence, even though Kagan has relevant expertise, he is not a clinician, and therefore is an outsider when it comes to the practice of psychiatry. He also does not seem to be up to date on the neuroscience of ADHD.

Yet his recent interview with Spiegel is being widely reports as definitive criticism of the diagnosis and treatment of ADHD. Here are some of the highlights: He says:

Let’s go back 50 years. We have a 7-year-old child who is bored in school and disrupts classes. Back then, he was called lazy. Today, he is said to suffer from ADHD (Attention Deficit Hyperactivity Disorder). That’s why the numbers have soared.

We are familiar with a similar criticism of autism diagnoses. Yes, diagnostic practices have changed. Awareness of the diagnosis has changed. The implication here is that the 1950s diagnosis (a bored child) was better than the current diagnosis of ADHD.

But, if you recall the diagnostic criteria from above, displaying ADHD behavior in school alone is not sufficient to establish the diagnosis. So, Kagan’s example is simply wrong. The child in his example should not be diagnosed with ADHD.

Being generous, he may be implying only that doctors are overdiagnosing ADHD and not following their own diagnostic criteria. This is a real issue, but here is a far more nuanced discussion from an actual clinician:

ADHD is real—it’s not made up. But it exists on a continuum. There’s no marker or white line that says you’re in the “definite” or “highly likely” group. There’s almost unanimous agreement that five or six percent clearly have enough of these symptoms for an ADHD diagnosis. Then there’s the next group, where the diagnosis is more of a judgment call, and for these kids, behavioral therapy might work. And then there’s a third group, on the borderline. These are the ones we’re worried about being pushed into an inaccurate diagnosis.

The real issue is – are schools pushing for more kids in the gray zone to be diagnosed because of funding and regulation issues? Also, there is a real “demarcation problem” with the diagnosis, and we have to carefully consider the risks and benefits of using looser or tighter criteria. These discussions are happening within the profession, and are very evidence-based and nuanced. Kagan’s criticism, by comparison, is shooting from the hip and simplistic. (I will add the caveat that the interview may not reflect the full depth of his opinion, but he is responsible for how he communicates to the public, especially given how widely his opinions have been spread.)

He continues:

SPIEGEL: Experts speak of 5.4 million American children who display the symptoms typical of ADHD. Are you saying that this mental disorder is just an invention?

Kagan: That’s correct; it is an invention. Every child who’s not doing well in school is sent to see a pediatrician, and the pediatrician says: “It’s ADHD; here’s Ritalin.” In fact, 90 percent of these 5.4 million kids don’t have an abnormal dopamine metabolism. The problem is, if a drug is available to doctors, they’ll make the corresponding diagnosis.

That characterization, while you might dismiss it as hyperbole, is irresponsible. “Every” child? Again, this does not meet the official diagnostic criteria for ADHD which requires more than just not doing well in school. His reference to “dopamine metabolism” is just weird. It is true that some studies show some children with ADHD have impaired reward system function. This may be playing a role in some subtypes of ADHD. It is not a core feature of ADHD, however, and the evidence is still very preliminary. Invoking what is essentially a preliminary side point about the neuroanatomical correlates of ADHD as reason to doubt the diagnosis is, to be kind, highly problematic.

Kagan then broadens his criticism to encompass psychiatry in general:

We could get philosophical and ask ourselves: “What does mental illness mean?” If you do interviews with children and adolescents aged 12 to 19, then 40 percent can be categorized as anxious or depressed. But if you take a closer look and ask how many of them are seriously impaired by this, the number shrinks to 8 percent. Describing every child who is depressed or anxious as being mentally ill is ridiculous. Adolescents are anxious, that’s normal. They don’t know what college to go to. Their boyfriend or girlfriend just stood them up. Being sad or anxious is just as much a part of life as anger or sexual frustration.

This is a typical anti-mental illness statement. This is simply a straw man of what psychiatry does.

He is saying that we should not confuse the normal range of behavior with a disorder, as if this is a huge insight. This understanding has already been incorporated into clinical thinking. As I pointed out above – there are great pains taken when defining mental disorders to separate true disorders from the healthy range of human behavior.

Further, being “seriously impaired” is already part of the diagnosis, so what is he talking about?

He goes on to argue that some people are depressed in response to a life event. Right – psychiatrists call this a “reactive depression” because it is already recognized, and not confused with a chronic depression. That is why the diagnosis of clinical depression excludes depression that follows a major trigger, and must continue for greater than six months to be considered a disorder.

From reading the entire interview I am left wondering, exactly what Kagan is criticizing? He is certainly not criticizing the standard of care within psychiatry. He seems to be tilting at a straw man of the worst possible malpractice that deviates from that standard. He is raising issues as if these are not already part of a vigorous evidence-based discussion within psychiatry itself.

A kernel of truth

We often take a sharply critical approach to medical science here at SBM. Self-criticism is critical to improvement. That is the essence of science itself, it is designed for error correction through self-criticism.

Our nuanced position is that science basically works, but there is a lot of room for improvement. Enemies of science, however, or those with a specific ideological axe to grind, use the same evidence to argue that the institution of science is fatally flawed and can be comfortably dismissed or ignored.

I find the same is true of much of the public criticism of psychiatry. There is a lot to criticize in the profession (as in medicine in general), and a lot of room for improvement. Some of that is just the current status of the science. We don’t know everything, and yet medicine (including psychiatry) is an applied science. We have to make important decisions with limited information.

There are also many issues of quality control. Medicine is hard, and keeping quality standards high is challenging.

So there are many legitimate criticisms of ADHD and psychiatry, but that does not mean ADHD is a fraud. The scientific evidence, both clinical and neuroscience, is robust. Kagan’s criticisms are mostly greatly exaggerated, or they are straw men because they are already incorporated into the standard of care.

Unfortunately, you will not be exposed to any of that from reading any of the popular press breathlessly reporting that ADHD is a fraud.

Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the president and co-founder of the New England Skeptical Society, the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also contributes every Sunday to The Rogues Gallery, the official blog of the SGU.