Researchers at Rhode Island Hospital and Brown University found that fewer than half of patients previously diagnosed with bipolar disorder were assessed using a comprehensive psychiatric diagnostic interview - the Structured Clinical Interview for DSM-IV (SCID).
This contradicts recent reports which suggest that under-diagnosis of bipolar disorder is an issue; while this study indicates that there's an equal or greater problem with over diagnosis.
Professor Michael Simpson, Health24's CyberShrink agrees and says that just from experience on the CyberShrink Forum it "appears as though almost everyone is being diagnosed with bipolar disorder".
Bipolar disorder becoming a 'popular' illness?
"If they don't get diagnosed with the disorder by the doctor, they self-diagnose. I have also noticed that many of these people seem to be on more medication than may be necessary – and it's usually of the newest and most expensive variety too," he said.
Simpson added that when he trained, bipolar disorder was a largely rare and mainly underdiagnosed illness, but that recently it's 'enormously' overdiagnosed.
This is consistent with the study which was published online in The Journal of Clinical Psychiatry and was presented at the American Psychiatric Association annual meeting, in Washington, D.C.
How the study was done
In the study, researchers looked at 700 psychiatric patients who were interviewed using the SCID and completed a self-administered questionnaire between May 2001 and March 2005.
The questionnaire asked patients if they'd been previously diagnosed with bipolar or manic-depressive disorder by a healthcare professional.
While 145 of the patients said they'd been previously diagnosed with bipolar disorder, only 43.4 percent were diagnosed based on the SCID. The study also found that people diagnosed based on the SCID were much more likely to have first-degree relatives with the disorder.
'Bipolar is a serious illness'
One problem with people self-diagnosing or being misdiagnosed with bipolar disorder is that it's undermining the serious nature of the disorder. "It seems that people who are depressed are being diagnosed as bipolar, but this is only one 'pole' and is therefore not bipolar disorder. One has to have a history of highs and lows to be thought of as bipolar," said Simpson.
Wrong diagnosis could lead to wrong medication
The danger involved with overdiagnosis of bipolar disorder is that this may lead to unnecessary use of medications and therefore increase the risk of harmful side effects.
The lead author of the study, Dr Mark Zimmerman (director of outpatient psychiatry at Rhode Island Hospital; associate professor of psychiatry and human behaviour at Brown University), said one reason for the number of patients being overdiagnosed might be due to "Clinicians being inclined to diagnose disorders that they feel more comfortable treating.
"We hypothesised 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," Zimmerman said.
Simpson held a similar view and said that the newer and most expensive medications were not always the best route to go as many of the older medications used to treat the disorder were still effective.
"Usually counselling and antidepressant medication is what's commonly advised for people recently diagnosed with bipolar disorder, but I am seeing people with three or four different mood drugs as well as antidepressants and I am very suspicious of what role marketing by the pharmaceutical companies plays. "Lithium, which has been prescribed since the 1950s, is still a very good drug to treat this condition. I actually think it's better to user 'older' drugs as we already know the risks and problems associated with them. Newer drugs should only be used if the older ones proved ineffective," he said.
Marketing influences meds docs prescribe
Zimmerman says that the bias doctors seem to be showing towards the newer drugs is "often reinforced by the marketing message of pharmaceutical companies to physicians, which has emphasised the literature on the delayed and under-recognition of bipolar disorder, and may be sensitising clinicians to avoid missing the diagnosis of bipolar disorder."
"The results of this study suggest that bipolar disorder is being overdiagnosed, and we recommend that clinicians use a standardised, validated method in diagnosing bipolar disorder," he concluded.
Source: Professor Michael Simpson, aka CyberShrink; Sapa
(Amy Henderson, Health24.com, May 2008)
Read more: A case study on bipolar disorder
The stigma of mental illness