Bipolar express: mental ailment expands rapidly among youth.

The rate of bipolar disorder diagnoses for children and adolescents seen as outpatients by physicians shot up dramatically between 1994 and 2003, raising new concerns about possible overdiagnosis of this severe mood disorder among young people.

National medical surveys done during that time period show that the number of office visits that resulted in a bipolar diagnosis for kids and teens increased by a factor of 40, say psychiatrist Mark Olfson of Columbia University and his coworkers. That figure far exceeds the doubling of bipolar diagnoses for adults over the same stretch, the researchers add.

The team's findings appear in the September Archives of General Psychiatry.

Further research needs to examine how physicians decide that a child's emotional travails qualify as bipolar disorder and how often youngsters with other mental disorders get misclassified as bipolar, the investigators suggest.

"It's likely that this impressive increase reflects a recent tendency to overdiagnose bipolar disorder in young people, a correction of historical underrecognition [of the disorder], or a combination of both," Olfson says.

His team probed data from an annual nationwide survey of about 1,200 office-based physicians. The scientists focused on information from every second year from 1994 through 2003.

They estimate that during that period, the number of office visits yielding a bipolar diagnosis for patients age 19 or younger jumped from 25 out of every 100,000 to 1,003 out of every 100,000. For adults, the number of office visits resulting in a bipolar diagnosis increased from 905 per 100,000 to 1,679 per 100,000.

Since the national survey records data for office visits rather than for individual patients, an unknown number of youth and adults were counted more than once, Olfson cautions.

About two-thirds of youth visits that produced a bipolar diagnosis were made by males. In contrast, females accounted for most adult-bipolar diagnoses.

In addition, one-third of young people given a bipolar diagnosis also received a diagnosis of attention-deficit hyperactivity disorder (ADHD), compared with only 3 percent of bipolar adults.

Some ADHD symptoms, such as an elated mood and extreme excitability, overlap with the manic symptoms of bipolar disorder. Prior studies have suggested that physicians may mistake ADHD as well as mild manic symptoms displayed by some adolescents for bipolar disorder.

Whatever accounts for the national diagnostic trend, Olfson's team found that most youngsters and adults diagnosed with bipolar disorder received prescriptions for the same psychoactive medications. Comparable proportions of both age groups received prescriptions for lithium, anticonvulsants, antidepressants, and antipsychotics.

Much research has outlined treatment guidelines for adult-bipolar disorder. The new report underscores the need to study the safety and effectiveness of medications commonly prescribed to youth with bipolar disorder, Olfson says.

Diagnostic trends described in Olfson's study may partly reflect increased accuracy in adolescent-bipolar disorder diagnoses, comments psychiatrist Melissa P. DelBello of the University of Cincinnati College of Medicine. Overdiagnosis might also occur, but such cases need to be confirmed through detailed psychiatric interviews of kids and teens dubbed bipolar by physicians, DelBello says.