Bipolar disorder: the shift to overdiagnosis

Abstract

Sometimes dramatically changing vogues in diagnostic practice in psychiatry resemble the volatility of international share markets. One such quickly shifting diagnostic area has been that of bipolar disorder (BD). Historically regarded as a relatively uncommon condition until recent decades, the construct of BD underwent a major expansion in the 1990s and 2000s with promulgation of the concept of the soft bipolar spectrum disorder, from which the recent research focus on subthreshold BD presentations was derived. Related to this has been renewed interest in treatments for BD from the pharmaceutical industry. The increasing rates of diagnosis have largely related to BD II, for which there has been a dramatic broadening of diagnostic criteria. This article critically reviews research data, both for broadening the diagnostic criteria for BD and, conversely, for the growing evidence of overdiagnosis in clinical practice. Why does this debate matter? I would suggest that there are many valid reasons to be concerned about overdiagnosis: first, the potential for overtreatment or inappropriate treatment of such patients with mood stabilizing treatments, including antipsychotics; second, the potential for diagnostic oversimplification, with consequent diagnostic deskilling and loss of credibility for the psychiatric profession; and third, the potential major impact on etiologic research for this condition. Psychiatry should not uncritically accept the shift to overdiagnosis, which has developed a rapid momentum in recent decades, in both clinical and academic circles. We must ensure, as a profession, that any change in diagnostic practice is underpinned by rigorous and critical research inquiry.