The number of U.S. children and adolescents treated for bipolar disorder increased 40-fold from 1994 to 2003, researchers report today in the most comprehensive study of the controversial diagnosis.
Experts say the number has almost certainly risen further since 2003.
Many experts theorize that the jump reflects that doctors are more aggressively applying the diagnosis to children and not that the incidence of the disorder has increased.
But the magnitude of the increase is surprising to many psychiatrists. They say it is likely to intensify the debate over the validity of the diagnosis, which has shaken child psychiatry.
Bipolar disorder is characterized by extreme mood swings. Until relatively recently, it was thought to emerge almost exclusively in adulthood. But in the 1990s, psychiatrists began looking more closely for symptoms in younger patients.
Some experts say greater awareness, reflected in the increasing diagnoses, is letting children with the disorder obtain the treatment they need.
Other experts say bipolar disorder is over-diagnosed. The term, the critics say, has become a catchall applied to almost any explosive, aggressive child.
After children are classified, the experts add, they are treated with powerful psychiatric drugs that have few proven benefits in children and potentially serious side effects like rapid weight gain.
In the study, researchers from New York, Maryland and Madrid analyzed a National Center for Health Statistics survey of office visits that focused on doctors in private or group practices. The researchers calculated the number of visits in which doctors recorded diagnoses of bipolar disorder and found that they increased, from 20,000 in 1994 to 800,000 in 2003, about 1 percent of the population under age 20.
The spread of the diagnosis is a boon to drug makers, some psychiatrists point out, because treatments include medications that can be three to five times more expensive than those for other disorders like depression or anxiety.
“I think the increase shows that the field is maturing when it comes to recognizing pediatric bipolar disorder, but the tremendous controversy reflects the fact that we haven’t matured enough,” said Dr. John March, chief of child and adolescent psychiatry at the Duke University School of Medicine, who was not involved in the research.
“From a developmental point of view,” March said, “we simply don’t know how accurately we can diagnose bipolar disorder or whether those diagnosed at age 5 or 6 or 7 will grow up to be adults with the illness. The label may or may not reflect reality.”
Most children who qualify for the diagnosis do not proceed to develop the classic features of adult bipolar disorder such as mania, researchers have found. They are far more likely to become depressed.
Dr. Mani Pavuluri, director of the pediatric mood disorders program at the University of Illinois, Chicago, said the label was often better than any of the other diagnoses often given to difficult children.
“These are kids that have rage, anger, bubbling emotions that are just intolerable for them, and it is good that this is finally being recognized as part of a single disorder,” Pavuluri said.
“I have been studying trends in mental health services for some time, and this finding really stands out as one of the most striking increases in this short a time,” said Dr. Mark Olfson of the New York State Psychiatric Institute at the Columbia University Medical Center, the senior author of the study.
The increase makes bipolar disorder more common among children than clinical depression, the authors said. Psychiatrists made almost 90 percent of the diagnoses, and two-thirds of the young patients were boys, says the study, published in the September issue of the Archives of General Psychiatry. About half the patients were identified as having other mental difficulties, most often attention deficit disorder.
The children’s treatments almost always included medication. About half received anti-psychotic drugs such as Risperdal from Janssen or Seroquel from Astrazeneca, both developed to treat schizophrenia. A third were prescribed so-called mood stabilizers, most often the epilepsy drug Depakote.
Most children took a combination of two or more drugs, and four in 10 received psychotherapy.
The increased children’s diagnoses reflect several factors, experts say. Symptoms appear earlier in life than previously thought, in teenagers and young children who later develop the full-scale disorder, recent studies suggest.
In addition, drug makers and company-sponsored psychiatrists have been encouraging doctors to look for the disorder.
“We are just inundated with stuff from drug companies, publications, throwaways, that tell us six ways from Sunday that, `Oh my God, we’re missing bipolar,’ ” said Dr. Gabrielle Carlson, a professor of psychiatry and pediatrics at Stony Brook University School of Medicine on Long Island. “And if you’re a parent with a difficult child, you go online, and there’s a Web site for bipolar, and you think: `Thank God I’ve found a diagnosis. I’ve found a home.’ “
