TUESDAY, Sept. 4, 2007 (HealthDay News) -- The number of young people treated for bipolar disorder increased 40-fold in the United States between 1994 and 2003, according to a new study.
But even one of the authors of the report in the September issue of Archives of General Psychiatry isn't certain whether this represents a dramatic increase in the number of people who actually have the disorder.
"There is no evidence that there has been an increase in bipolar disorder of this size," said Dr. Mark Olfson, a clinical psychiatry professor at New York State Psychiatric Institute and one of the authors of a report. "Either this increase we see represents a tendency for over-diagnosing recently or a tendency to under-diagnose in the past."
"It's a combination of both," added Dr. Glenn Hirsch, medical director of the New York University Child Study Center. "It has clearly been under-diagnosed in the past. A variety of surveys have said over and over that up to 70 percent of adults with the disorder report that their symptoms began early."
Bipolar disorder is a condition in which people swing from periods of mania, an abnormally elevated mood, to depression. It originally was called manic depression.
The researchers analyzed data from a national survey of office-based physicians, comparing the rate of growth in diagnoses of bipolar disorder. For individuals 19 and under, a diagnosis of bipolar disorder was made in 25 of 100,000 visits (about 20,000 patients) in 1994-1995.
That number grew to 1,003 per 100,000 visits (about 800,000 patients) in 2002-2003.
By contrast, during the same time frame, adult diagnoses of bipolar disorder doubled, from 905 visit to 1,679 visits per 100,000 population.
Is there an explanation for such an explosion in the number of young people diagnosed with bipolar disorder?
"What this means is that psychiatrists are increasingly comfortable diagnosing children with bipolar disorder," said Dr. David Axelson, director of the Child and Adolescent Bipolar Services clinic at the University of Pittsburgh School of Medicine. "But it is impossible to know whether those diagnoses are correct or not without external confirmation."
Bipolar disorder is an elusive condition, Axelson said, difficult to pin down because there is no specific diagnostic test.
Until recently, it was easy to miss the first signs of bipolar disorder in a young person, because it often is a mild depressive episode that might not be seen as pathological, Hirsch said. "Irritability and depressive behavior may be a form of bipolar disorder," he added. "A child who has feelings of aggression, irritation and anger may have bipolar disorder."
One reason for the increase in diagnoses is that physicians are becoming aware that such cases do not fit the textbook description, Hirsch said. "I suspect that the majority of cases we are seeing are in that unspecified area. We are still not sure what criteria we should be thinking of when we diagnose bipolar disorder, " he added.
It's important to get the diagnosis right, Axelson said, because some medications prescribed for other conditions could make bipolar disorder worse.
"Physicians should bring greater rigor to bear," Hirsch said. "Parents should be aware there has been this big increase in diagnoses. They should ask why and how such a diagnosis is made and what decisions went into it, and they should know more about the medications."
To learn more about bipolar disorder, visit the National Institute of Mental Health.