PROVIDENCE – A new study by Rhode Island Hospital and Brown University researchers to be presented at the American Psychiatric Association annual meeting this week suggests that a large share of people diagnosed with bipolar disorder are not evaluated thoroughly enough.
The study is based on data from 700 psychiatric outpatients who filled out questionnaires and underwent the Structured Clinical Interview for DSM-IV – a comprehensive psychiatric diagnostic interview – between May 2001 and March 2005.
The questionnaire asked whether they had been previously diagnosed with bipolar or manic-depressive disorder by a health care professional. Family history of bipolar disorder was used as an index of diagnostic validity.
Of the 700 patients, 145 reported they had been previously diagnosed as having bipolar disorder, but only 43.4 percent had gotten that diagnosis based on the comprehensive interview – and far more of that group had first-degree relatives with the disorder.
The researchers concluded that while recent reports indicate a problem with underdiagnosis of bipolar disorder, an equal or greater problem may exist with overdiagnosis.
The study was published online by the Journal of Clinical Psychiatry, and principal investigator Dr. Mark Zimmerman, director of outpatient psychiatry at Rhode Island Hospital and associate professor of psychiatry and human behavior at The Warren Alpert Medical School of Brown University, is to present the findings at the annual meeting of the American Psychiatric Association this Wednesday.
Because bipolar disorder is treated primarily with drugs that stabilize patients’ moods, being diagnosed incorrectly with the disorder would unnecessarily expose patients to serious medication side effects, including possible impact to renal, endocrine, hepatic, immunologic and metabolic functions.
“Clinicians are inclined to diagnose disorders that they feel more comfortable treating,” Zimmerman said in a news release. “We hypothesize that the increased availability of medications that have been approved for the treatment of bipolar disorder might be influencing clinicians who are unsure whether or not a patient has bipolar disorder or borderline personality disorder to err on the side of diagnosing the disorder that is medication responsive.”
That bias, Zimmerman added, “is reinforced by the marketing message of pharmaceutical companies to physicians, which has emphasized the literature on the delayed and underrecognition of bipolar disorder, and may be sensitizing clinicians to avoid missing the diagnosis of bipolar disorder.”
The study is part of the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) Project, for which Zimmerman is the principal investigator.
Rhode Island Hospital is a private, not-for-profit hospital and is the largest teaching hospital associated with The Warren Alpert Medical School of Brown University. For more information, go to www.lifespan.org and www.brown.edu.
