The number of visits to a doctor's office that resulted in a diagnosis of bipolar disorder in children and adolescents has increased by 40 times over the last decade, reported researchers funded in part by the National Institutes of Health (NIH).
Over the same time period, the number of visits by adults resulting in a bipolar disorder diagnosis almost doubled. The cause of these increases is unclear. Medication prescription patterns for the two groups were similar. The study was published in the September 2007 issue of the Archives of General Psychiatry.
Mark Olfson, M.D., M.P.H., of New York State Psychiatric Institute of Columbia University, along with National Institute of Mental Health (NIMH) researcher Gonzalo Laje, M.D., and their colleagues examined 10 years of data from the National Ambulatory Medical Care Survey (NAMCS), an annual, nationwide survey of visits to doctors' offices over a one-week period, conducted by the National Center for Health Statistics. The researchers estimated that in the United States from 1994–1995, the number of office visits resulting in a diagnosis of bipolar disorder ( http://www.nimh.nih.gov/healthinformation/bipolarmenu.cfm) was 25 out of every 100,000 for youths ages 19 and younger. By 2002–2003, the number had jumped to 1,003 per 100,000 youth visits. In contrast, for adults ages 20 and older, 905 per 100,000 office visits resulted in a bipolar disorder diagnosis in 1994–1995; a decade later the number had risen to 1,679 per 100,000 visits.
While the increase in bipolar diagnoses in youth far outpaces the increase in diagnosis among adults, the researchers are cautious about interpreting these data as an actual rise in the number of people who have the illness (prevalence) or the number of new cases each year (incidence).
"It is likely that this impressive increase reflects a recent tendency to overdiagnose bipolar disorder in young people, a correction of historical under recognition, or a combination of these trends. Clearly, we need to learn more about what criteria physicians in the community are actually using to diagnose bipolar disorder in children and adolescents and how physicians are arriving at decisions concerning clinical management," said Dr. Olfson.
The fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) provide general guidelines that can help doctors identify bipolar disorder in young patients. However, some studies show that youths with symptoms of mania (over-excited, elated mood) - one of the classic signs of bipolar disorder - often do not meet the full criteria for a diagnosis of bipolar disorder. Other disorders, such as attention-deficit hyperactivity disorder (ADHD) (http://www.nimh.nih.gov/healthinformation/adhdmenu.cfm), may have symptoms that overlap, so some of these conditions may be mistaken for bipolar disorder as well. For example, in a study conducted in 2001, nearly one-half of bipolar diagnoses in adolescent inpatients made by community clinicians were later re-classified as other mental disorders.
Of the medications studied, mood stabilizers, including lithium - which was the only medication approved at the time of the study by the U.S. Food and Drug Administration for treating bipolar disorder in children - were prescribed in two-thirds of the visits by youth and adults. Anticonvulsant medications, such as valproate (Depakote) and carbamazepine (Tegretol), were the most frequently prescribed type of mood stabilizers in both groups.
Doctors prescribed antidepressant medications in slightly over one-third of visits by youth and adults. Antidepressant medications include the older classes of antidepressant medications, such as tricyclics, tetracyclics, and monoamine oxidase inhibitors (MAOIs); selective serontonin reuptake inhibitors, such as fluoxetine (Prozac) and paroxetine (Paxil); and also newer types of antidepressants, including venlafaxine (Effexor). In both age groups, about one-third of the visits where antidepressant medications were prescribed did not include prescription of a mood stabilizer. This trend raises concerns, considering an earlier NIMH-funded study (Thase & Sachs, 2000) which reported that treating adults who have bipolar disorder with an antidepressant in the absence of a mood stabilizer may put them at risk of switching to mania. Also, a recent NIMH study showed that for depressed adults with bipolar disorder who are taking a mood stabilizer, adding an antidepressant medication was no more effective in managing bipolar symptoms (http://www.nimh.nih.gov/press/stepbd-medication.cfm) than a placebo (sugar pill).
Roughly the same percentage of youth and adult bipolar visits included a prescription for an antipsychotic medication, although young patients were more likely to be prescribed one of the newer, atypical antipsychotic medications, such as aripiprazole (Abilify) or olanzapine (Zyprexa), than other types of antipsychotics. This finding suggests that doctors may be basing their treatment choices for bipolar youth on prescribing practices for adults with the disorder.
However, one main difference between youth and adult treatment was that children and teens were more likely than adults to be prescribed a stimulant medication - usually prescribed for treating ADHD - and adults were more likely than youth to be prescribed benzodiazepines, a type of medication used to treat anxiety disorders (http://www.nimh.nih.gov/healthinformation/anxietymenu.cfm). More than half of all diagnosed youths and adults were prescribed a combination of medications. Given the relative lack of studies on appropriate treatments for youth with bipolar disorder, the researchers noted the urgent need for more research on the safety and effectiveness of medication treatments that are commonly prescribed to this age group.
The study had several important limitations. For example, the survey relied on the judgment of the treating physicians, rather than an independent assessment. As a result, the researchers' findings reveal more about patterns in diagnosis among office-based doctors than about definitive numbers of people affected by the illness. Another limitation is that the survey recorded the number of office visits instead of the number of individual patients, so some people may have been counted more than once.
"A forty-fold increase in the diagnosis of bipolar disorder in children and adolescents is worrisome," said NIMH Director Thomas R. Insel, M.D. "We do not know how much of this increase reflects earlier under-diagnosis, current over-diagnosis, possibly a true increase in prevalence of this illness, or some combination of these factors. However, these new results confirm what we are hearing increasingly from families who tell us about disabling, sometimes dangerous psychiatric symptoms in their children. This report reminds us of the need for research that validates the diagnosis of bipolar disorder and other disorders in children and the importance of developing treatments that are safe, effective, and feasible for use in primary care."
"This research, performed at a National Center on Minority Health and Health Disparities Center of Excellence, underscores the need to fully engage the community with their health care providers to better understand the actual prevalence of bipolar disease in children and adolescents," said John Ruffin, Ph.D., Director of NCMHD.