May 6, 2008 (Washington) -- Many people who have been told by their doctors that they have bipolar disorder don't really have it.
So say researchers who used a standardized, comprehensive, psychiatric diagnostic interview to evaluate 700 adult psychiatric outpatients.
About 20% had previously been diagnosed with bipolar disorder. But only 13% met the criteria, says Mark Zimmerman, MD, associate professor of psychiatry and human behavior at the Warren Alpert Medical School of Brown University in Providence and practicing psychiatrist at Rhode Island Hospital in Providence.
"In about half of patients previously diagnosed with bipolar disorder, we couldn't confirm the diagnosis," he tells WebMD.
There are real dangers to overdiagnosis, chief among them unnecessary exposure to mood stabilizers and all their powerful side effects, Zimmerman says. There's also the stigmatization of having a serious, possibly lifelong mental illness.
The study is being published online by the Journal of Clinical Psychiatry and presented at the annual meeting of the American Psychiatric Association.
Why Is Bipolar Disorder Overdiagnosed?
Bipolar disorder used to be called manic depression because it is characterized by bouts of depression and bouts of mania. Patients experience dramatic mood swings between euphoria and severe depression; they may have hallucinations or delusions.
Patients with anxiety, agitation, irritability, and restlessness that does not persist are sometimes misdiagnosed with bipolar disorder, Zimmerman says.
"These could be symptoms of bipolar disorder. But they really have to be accompanied by other criteria, such as hyperactivity, feeling energetic despite just a few hours of sleep, or inflated self-esteem," he says.
Ironically, one reason the disorder is being overdiagnosed is "because so much has been written about it being under-recognized," Zimmerman says.
"It's difficult to go to a lecture on bipolar disorder that doesn't begin with, 'Make sure you don't miss...,'" he says. "So clinicians are loathe to miss it."
The increased availability of medications for the treatment of bipolar disorder may also play a role in overdiagnosis, Zimmerman says. "Physicians have a tendency to diagnose something that they feel they comfortable treating," he says.
So what should you do if you think you've been misdiagnosed with bipolar disorder?
"If you're at all uncertain about the diagnosis, speak to your doctor and make sure you understand why you've been given that diagnosis. If you remain unconvinced, get a second opinion," Zimmerman says.
What you shouldn't do, he stresses, is just stop taking your medication.
Children Misdiagnosed, Too
For the study, psychiatric outpatients completed a questionnaire that asked whether they had ever been diagnosed with bipolar or manic-depressive disorder by a health care professional.
Then, without knowing the responses, the researchers used a tool called the Structured Clinical Interview for DSM-IV (SCID) to determine if the patients met the criteria for bipolar disorder.
"The standardized nature of the SCID interview forces the clinician not to miss things that could be missed in an unstructured interview," Zimmerman says.
National Institute of Mental Health Director Thomas Insel, MD, says misdiagnosis of bipolar disorder is a problem in children as well as adults.
"In children, it can be even more difficult to recognize and diagnose because it does not fit precisely the symptom criteria established for adults," he tells WebMD.