Diagnoses of bipolar disorder in children and adolescents have risen fortyfold since 1994, according to a new study released yesterday. Researchers attributed the rise in part to overdiagnosis of the serious psychiatric disorder.
The report in the journal Archives of General Psychiatry said bipolar disorder was found during 1,003 of every 100,000 office visits by children and adolescents, compared with 25 of 100,000 office visits in 1994.
The diagnosis of bipolar disorder among adults increased twofold during the same period, researchers said.
The study did not investigate the reasons for the explosion in bipolar cases among children and adolescents, which began after the 1998 publication of The Bipolar Child, a book that said one-third to one-half of children with depression had bipolar disorder.
Dr. Mark Olfson , a psychiatrist at Columbia University's College of Physicians and Surgeons and senior author of the latest study, said part of the increase can be attributed to underdiagnosis of bipolar disorder in the past.
Another reason, Olfson said, is mislabeling as bipolar children and adolescents with aggressive or irritable behaviors.
Dr. Thomas R. Insel, director of the National Institute of Mental Health, which funded the study, called the increase in bipolar 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."
Bipolar disorder, which is treated with powerful psychotropic medications, is marked by severe mood swings between depression and mania. It is characterized by an excess of energy and restlessness. For most patients, depressive episodes are three times more common and longer-lasting than those of mania. Symptoms of the disorder can interfere with daily activities, and in severe cases there is an increased danger of suicide.
Until recently, the illness, which appears to run in families, was seldom diagnosed in children. It was believed to begin in late adolescence or early adulthood. About 2 percent of American adults are believed to have bipolar disorder.
In the most recent study, researchers analyzed data from an annual national survey of the nature of patient visits to doctors. Researchers found that among children and adolescents, bipolar diagnoses were more common among boys. Among adults, they found, the illness is more common in women.
Olfson said the gender difference between the groups suggested that some boys with behavior problems or conduct disorders are being misdiagnosed as bipolar. Irritability is a characteristic of bipolar disorder, he said, but it also is a normal part of adolescence.
Dr. Gabrielle A. Carlson , a psychiatrist at Stony Brook University in New York, said one in every five children referred to her with a diagnosis of bipolar disorder has the disease. The rest, she said, have autism, depression, anxiety or another psychological disorder. All of those conditions involve different treatments with drugs, behavioral therapy or both.
Carlson, who has studied the increase in bipolar diagnoses, said some parents seem to prefer a diagnosis of bipolar disorder because the illness, which is thought to be largely genetic, absolves them of blame.
"They don't have to deal with their chaos, their psychiatric disorder, their marital troubles or abuse," she said.
Denise Gellene writes for the Los Angeles Times.