Diagnostic errors common among patients with bipolar disorder

By Laura Cowen, medwireNews Reporter

Russian study data bolster the existing body of evidence showing that bipolar disorder is often misdiagnosed as depression.

Sergey Mosolov (Moscow Research Institute of Psychiatry) and colleagues found that 40.8% of 409 patients (mean age 48.4 years, 78.4% women) with a diagnosis of recurrent depressive disorder (RDD) actually had bipolar disorder, including 4.9% with bipolar I disorder and 35.9% with bipolar II disorder.

“This non-recognition may be due to the absence of formal diagnostic criteria for [bipolar II disorder] in the ICD-10,” suggest the researchers in Bipolar Disorders.

They add: “The consequences of misdiagnosis and inappropriate treatment with antidepressants include a deteriorating clinical course, an increased risk of rapid cycling, suicide, alcoholism, substance abuse, sexually transmitted infections, and criminal activity, and increased costs of care.”

Indeed, in the current study, 17% of patients with bipolar II disorder were treated with antidepressants.

The team used the Mini International Neuropsychiatric Interview and clinical assessment by psychiatrists to verify the patients’ current diagnoses. They then tested the sensitivity and specificity of the Russian versions of the hypomania checklist (HCL)-32 and Bipolarity Index to differentiate between patients with bipolar II disorder and RDD.

The HCL-32 detected bipolar disorder at the recommended cut-off of score of 14 with a sensitivity of 83.7% and specificity of 71.9%.

The sensitivity of the Bipolarity Index was 73.5% and the specificity was 72.3% at an optimal cut-off score calculated by the researchers of 22. They note that they were unable to use the recommended cut-off of 60 because no patient in the RDD group and only four in the bipolar II disorder group obtained a total score above 60.

These findings indicate that the HCL-32 and the Bipolarity Index “could be useful” as additional tools for bipolarity screening, Mosolov and co-authors remark.

There were no statistically significant demographic differences between the patients with bipolar II disorder and those with RDD, but the time from onset of illness to correct diagnosis was significantly longer for the latter patients (15 years) than for those with RDD (12 years).

The researchers note that their findings may be limited by the fact that the majority (90.2%) of the patients included in the study were inpatients.

They conclude that development of ICD criteria for bipolar II disorder, epidemiological studies and educational programs to improve diagnosis of the condition are needed.

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