IMAGINE an eight-year-old boy whom we will call Eric. He is irritable and talks incessantly. Unable to sit still and concentrate, he does poorly at school. Nevertheless, he claims to be one of the smartest kids in the world and blames his poor academic performance on his “horrible” teachers. There are periods when his mood changes abruptly from euphoria to depression and then swings back again. Eric's symptoms qualify him for a diagnosis of bipolar disorder, which is characterized by episodes of full-blown mania or a less severe form called hypomania. These moods usually alternate with periods of depression [see box on opposite page].

Until about 1980 most mental health professionals believed that bipolar disorder did not occur in children. Although a few still hold this view, the general opinion of the psychiatric community has drastically shifted over the past 30 years, a period in which diagnoses of the disorder in kids have skyrocketed. In a study published in 2007 psychiatrist Carmen Moreno, then at Gregorio Marañón University General Hospital in Madrid, and her colleagues found a 40-fold increase between 1994 and 2003 in the number of visits to a psychiatrist in which a patient younger than 19 was given this diagnosis. By 2003, the researchers reported, the number of office visits resulting in a bipolar diagnosis in these youths had risen from 25 per 100,000 people to 1,003 per 100,000 people, a rate almost as high as that for adults.

Such data have sparked widespread concern that the condition is egregiously overdiagnosed, perhaps contributing to the use of ineffective and even harmful medical treatments. In this column, we discuss controversies regarding the overdiagnosis of bipolar disorder in children and recent attempts to remedy this situation.

Tale of Two Maniacs

In 1980 the American Psychiatric Association came out with a radically revised third edition of its diagnostic bible, the Diagnostic and Statistical Manual of Mental Disorders (DSM-III). This edition debuted the term “bipolar disorder” as a replacement for the earlier term “manic-depressive disorder.” The diagnosis required a full-blown manic episode lasting at least a week, usually alternating with periods of major depression that extended for at least two weeks. The symptoms had to be severe enough to interfere with social or occupational functioning; for children, the latter refers to how well they perform in school.

In the view of many professionals, some children did—and still do—fit these criteria. In 1994, however, with the publication of the DSM-IV, a new category of bipolar disorder appeared. In this volume, the one in use today, the illness is subdivided into bipolar I, essentially equivalent to the DSM-III version of this malady, and bipolar II, which has less stringent diagnostic criteria. A patient can be diagnosed with bipolar II if he or she has hypomania, the less severe form of mania, in which the manic episodes can be shorter—four days instead of a week—and do not impair functioning. The inclusion of this milder form of the disorder enabled many more children (as well as adults) to qualify for a bipolar diagnosis.

It is no coincidence then that the dramatic rise in cases of childhood bipolar disorder began as soon as the revised edition of the DSM landed on psychiatrists' desks. Many critics have raised concerns that this manual's loosened criteria have misclassified many children as bipolar II who had features too mild to really qualify them for any type of bipolar disorder—or who suffer from entirely different ailments.

Bad Diagnosis, Bad Treatment

Indeed, bipolar II overlaps substantially with other common childhood conditions. For example, attention-deficit hyperactivity disorder (ADHD) and bipolar are both characterized by distractibility, fidgeting, restlessness, high activity levels and excessive talking. Bipolar disorder also shares similarities with conduct disorder and oppositional defiant disorder, which are associated with repeated disruptive behaviors. Such overlaps can lead to misdiagnosis.

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The consequences of misdiagnosis are not trivial. Stimulant drugs such as Ritalin and Adderall, which are commonly used to treat ADHD, are not only ineffective for bipolar disorder but may worsen its symptoms or even trigger manic episodes. Meanwhile these drugs may produce side effects such as weight loss, insomnia and nervousness. On the other hand, a child with ADHD who is mistakenly diagnosed with bipolar disorder will usually be prescribed one or more of several medications, including lithium, anticonvulsants such as Depakote or Lamictal, or atypical antipsychotics (Abilify, Zyprexa). All these drugs are ineffective for ADHD and can cause side effects such as weight gain and involuntary movements. Rare but more serious problems such as seizures (from lithium) can show up when the dosage is too high.

Mood Shift

To reduce the problems of overlap and overdiagnosis, the authors of the DSM-5, to be published in 2013, have proposed adding a category called disruptive mood dysregulation disorder [see “Redefining Mental Illness,” by Ferris Jabr; Scientific American Mind, May/June 2012]. Symptoms of this illness would include frequent temper outbursts and chronically irritable, angry or sad moods. This addition could provide a diagnostic home for many children who would be excluded from a bipolar diagnosis but who did display some of its symptoms. With more accurate diagnosis, doctors hope, children in the two bipolar categories, as well as the new one, will receive more appropriate and therefore better treatment.

Despite the proliferation of categories, some children (those with symptoms like Eric's, for example) can be rightly diagnosed with bipolar disorder using stringent criteria. And no matter how they are labeled, children who display pathological mood swings experience significant distress and are in dire need of proper care.