The September 4, 2007, issue of the Los Angeles Times (online) reported that the diagnosis of bipolar disorder in children and adolescents has risen 40-fold since 1994, according to a new study. However, it also said that researchers partly attribute the dramatic rise to doctors over-diagnosing the serious psychiatric disorder.

In the report released the previous Monday in the Archives of General Psychiatry, researchers looked at the number of times that children younger than 19 years old went to the doctor and were diagnosed with or treated for bipolar disorder. They found that the number of such visits soared from an estimated 20,000 in 1994 to 800,000 in 2003.

Researchers said that the diagnosis of bipolar disorder among adults increased twofold during the same period.

The study did not investigate the reasons for the sharp increase in cases of bipolar disorder among children and adolescents, which began after the 1998 publication of the famous book called The Bipolar Child, by Demitri and Janice Papolos; a controversial book because it made the assertion that one-third to one-half of children with depression had bipolar disorder.

Dr. Mark Olfson, a psychiatrist at the College of Physicians and Surgeons at Columbia University, and senior author of the latest study, said that part of this reported increase can be attributed to an under-diagnosis of bipolar disorder in the past.

However, Olfson also said that another reason for the increase is the mislabeling of children and adolescents with aggressive or irritable behaviors as bipolar disorder.

Dr. Thomas Insel, who is the Director of the National Institute of Mental Health (NIMH) – which funded the study – called the increase in bipolar disorder diagnoses worrisome.

'The way the label is being used is probably a little exuberant - not fitting with the strict definition of the illness,' Insel said. The disorder 'is probably not as common as the very high rates we're seeing.'

Contrary to what Insel says, however, is that bipolar disorder affects up to 4.4% of the adult population of the United States. Until recently, the disorder, which is noted to run in families, was seldom diagnosed in children. It was believed to begin in late adolescence or early adulthood, but this could be because it was not reported until then. Now it is being reported as early as toddlerhood; some reports as early as infancy.

Researchers analyzed data for this latest study from an annual national survey that collects information from doctors about the nature of their patient visits. They found striking differences between children and adults. Among adults, bipolar disorder is more common in women. Among children and adolescents, boys were more likely to be diagnosed with the disorder.

According to the report, young people were ten times more likely to receive a diagnosis of attention deficit hyperactivity disorder (ADHD) than adults with bipolar disorder.

Olfson said it was likely that some children with ADHD received the additional diagnosis of bipolar disorder because the symptoms of the two illnesses overlapped. He said, for example, that some children and adolescents with ADHD have a 'volatile, aggressive subtype' that is easily confused with bipolar disorder.

In addition, symptoms of ADHD and the manic side of bipolar disorder are also similar.

Dr. Gabrielle Carlson , a psychiatrist at Stony Brook University in New York, said only one out of every five children referred to her with a diagnosis of bipolar disorder actually has it. The rest have autism, depression, anxiety or another psychological disorder.

Carlson said that in some cases, providers will diagnose psychological problems in children as bipolar disorder to obtain insurance reimbursement for hospitalizations, a practice called upcoding.

Insel said his institute is conducting research that might lead to more accurate diagnoses of bipolar disorder in young people. More and more young people are being diagnosed with bipolar disorder every day. In young people and children, it is sometimes called early-onset bipolar disorder; therefore, it may not be properly reported as bipolar disorder.

The agency said that recent imaging studies had detected differences between the brains of normal children and those with bipolar disorder.

A large study looking for the genes responsible for the disorder is nearing completion and may yield some additional clues, Insel said.

NOTE: The Associated Press contributed to this report, and the article referred to in this article also appeared in the San Francisco Chronicle.