Rise of ADHD in USA, is it buzzword?

Attention Deficit Hyperactivity Disorder (ADHD) is overwhelming in the USA. According to New York Times (NYT), it is revealed that nearly one-fifth of high school age boys has ADHD.

New York Times: A.D.H.D. Seen in 11% of U.S. Children as Diagnoses Rise

I think that the specialists of psychiatry deem this report as ridiculous. In Diagnostic and Statistical Manual of Mental Disorder 4th edition text revision (DSM-IV-TR), an authorized textbook edited by the American Psychiatric Association, the prevalence rate of ADHD is described as 3 to 7 % in school aged children.
The cause of ADHD is still unknown. There are hypotheses that some kinds of stress for pregnant women are risks of ADHD of their children. If it is true, it is possible that a certain substance (e.g. electric wave; I am doubtful) increase ADHDs. Nonetheless the result reported by the NYT is far from credible.

In Japan, the prevalence rate of ADHD is reported as 0.37% by Department of Health Promotion and Research, National Institute of Public Health (2005, in Japanese).

From my impression, number of the patients with ADHD is increasing indeed, but the prevalence rate is lower than 10%. To begin with, ADHD cannot be defined specifically with biological markers. If over 10 to 20 % of children were ADHDs, they would be ordinary, only with a few hyperactive characteristic!

There are some reasons of this high rate of statistics surveyed in the USA, I guess.

First, this survey is performed with telephone interviews with parents. As this article suggests, parents tend to overestimate about concern of their children.

Time: Understanding the Rise in ADHD Diagnoses: 11% of U.S. Children Are Affected

Second, over-diagnosis problem is pointed out in many areas in medicine. For example, in Japan the number of patients with mood disorders is doubled in this decade.

Is it true? I don’t think so. Several explanations are possible. For example, in 1990s a lot of mental clinics are established in Japan. It eased for patients suffering from depression to visit a clinic to be diagnosed.
Similarly, the prevalence rate of colon cancer is also increasing. It may result from progress of technology to use a microscope.

The matter about medication for ADHD also should not be forgotten. Methylphenidate is an effective drug to suppress symptoms of ADHD. However, this stimulant may cause severe adverse effects, such as dependency, even psychosis. In Japan, many patients and physicians misused methylphenidate. As a result, the government has restricted prescription of methylphenidate since 2007. In the USA some patients or non-patients might misuse this kind of drugs for their pleasure. Now more safe drugs such as Atomoxetine are available.

Actually, some explosions of a particular diagnosis are happening occasionally in psychiatric practice. Innovation in treatment may change diagnostic strategy. A political campaign also causes a fashion. Psychiatry is a region of science, but it is still premature. We have to continue to learn about it.