Is ADHD an American Fad?

The diagnosis of ADHD has become increasingly common in the United States — but experts say this condition is widespread in rest of the world too. Find out why.

Once ADHD was defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM), the guide to psychological disorders published by the American Psychiatric Association, diagnoses began to rise steadily. Stimulants such as Ritalin and Adderall turned out to be effective at ameliorating the symptoms of ADHD, particularly problems involving focus and hyperactivity, at least in the short term, and drug companies began to vigorously market these medications. 

But it wasn’t just U.S. doctors and clinicians who were beginning to recognize ADHD. At the same time ADHD was classified in the United States, it was defined in the World Health Organization’s counterpart to the DSM — the International Statistical Classification of Diseases and Related Health Problems (ICD). WHO’s definition was a bit more restrictive, though, so the rates of ADHD in the rest of the world seemed lower at first than the rates in the United States, says Faraone, adding that “the two definitions are becoming much more similar now.”

ADHD: Not a Simple Diagnosis

One of the problems in assessing the prevalence of ADHD is that there is no simple test to diagnose the disorder. The DSM instructs physicians to look for symptoms of hyperactivity and inattention that have persisted for at least six months and that interfere with a child’s ability to function in at least two areas of life, such as school and home. But the symptoms, such as “often talks excessively” and “often fidgets with hands or feet or squirms in seat when sitting still is expected,” sound an awful lot like the normal behavior of a child. It requires a skilled diagnostician to determine whether a child’s symptoms are causing real impairment.

Though teachers cannot make a diagnosis of ADHD, they can and do make recommendations about whether a child should be evaluated by a professional. A recent study from Michigan State University found that children born in the month prior to the cutoff date for kindergarten eligibility (i.e. typically the youngest and therefore most immature children within a grade) were far more likely to be diagnosed with ADHD compared to children born in the month immediately afterward. Therefore, some ADHD diagnoses may be “driven by teachers’ perceptions of poor behavior among the youngest children in a classroom” rather than true ADHD symptoms. Similar studies have fueled a suspicion among the public that ADHD is too frequently diagnosed and is diagnosed in a highly subjective manner. However, says Polanczyk, “The media approach misdiagnosis as if it is evidence that ADHD is not a valid disorder, which is absurd.”

And while most researchers believe that the disorder has a genetic component, they acknowledge that the context in which a child lives and goes to school may also contribute to ADHD symptoms. A 2005 WHO report on mental health, for instance, noted that the “diagnosis can be symptomatic of family dysfunction, rather than individual psychopathology, and may reflect inadequacies in the educational system.”

ADHD: Not Just an American Problem

In recent years, researchers have tried to understand the prevalence of ADHD across the globe. A number of papers have examined studies in different countries and found that when the same diagnostic criteria and research methods are used, the prevalence of the disorder is fairly consistent across cultures. Polanczyk and his colleagues, for example, considered more than 100 studies from around the world and found that prevalence of ADHD was influenced more by the methods of the individual studies than by geographic location. “Wherever people have looked for the disorder, they have found it,” says Faraone.

There is some variation, though, in overall estimates of ADHD. Polanczyk’s study, published in the June 2007 issue of the American Journal of Psychiatry, estimated that the worldwide prevalence of ADHD is 5.3 percent among children and adolescents. Faraone, who coauthored a study published in World Psychiatry in 2003 that examined the worldwide prevalence of ADHD, believes that the incidence may range between 8 percent and 12 percent.

Diagnosis and treatment of ADHD also differs in some countries, as indicated in a new study in the journal Psychiatric Services that surveyed nine nations. Researchers found that some countries, like the United Kingdom, use pychosocial treatment as a first-line approach while others, including Canada, are more likely to use medication.

ADHD: Not Just a Childhood Problem

ADHD — once believed to be a childhood disorder — seems to persist into adulthood in about two-thirds of cases. Kessler of Harvard Medical School conducted a study using national household survey data in the United States and found that 4.4 percent of adults met the criteria for ADHD — though diagnosis is tricky as results are based on self-reporting. “It’s a real thing with adults,” he says. The study, which was published in the American Journal of Psychiatry, found that adults who reported having had ADHD symptoms since childhood had other emotional problems too. Many of these adults were not receiving any treatment.

In another study published in The Clinical Neuropsycholgist, the researchers found that nearly 1 and 4 adults seeking ADHD treatment may be exaggerating or faking symptoms, most likely to obtain stimulant drugs.

Is ADHD Overdiagnosed?

While some cases may be misdiagnosed, many believe that ADHD is underdiagnosed as well, particularly among adults.

Clearly, a more rigorous system for diagnosing the disorder is needed. And parents, teachers, and physicians should be educated about what exactly ADHD is, and when a child or adult requires treatment.

But consider the days when depression was just starting to be treated with medications like Prozac — the public was horrified. There was a sense that depressed people were weak, popping pills to dampen normal human emotions like sadness and despair. And there was a concern that these medications could destroy or impair a person’s innate humanity. “It’s hard for people to believe,” says Faraone, “that normal human reactions could be at the root of a real disorder.”