Exploring treatment options such as N-acetylcysteine and bipolar-specific psychotherapies is on the horizon for this bipolar series. But with DSM-5 about to arrive, one more examination of bipolar diagnosis is warranted. After all, if a diagnosis is inaccurate, treatment efforts, however well-intentioned, may misfire.
The formal changes in DSM-5 will not be official or public until this month. But the bipolar disorder workgroup proposed 4 changes on the DSM-5 Web site (since removed in anticipation of publication).1 Two of the proposed changes will tighten bipolar diagnostic requirements, and two will loosen them.
The tightening criteria are (1) diagnosis of hypomania or mania will now require a finding of increased energy along with the rest of the unchanged criteria and (2) bipolar not otherwise specified (BP NOS) becomes bipolar not elsewhere classified (BP NEC), with tighter definitions of subthreshold bipolar variations. The loosening criteria are (1) mixed states will encompass a spectrum of admixtures of manic and depressive symptoms, down to specific minimums and (2) antidepressant-induced hypomania or mania will now qualify a patient for a diagnosis of bipolar disorder.
Will the tighter criteria help address the reported overdiagnosis problem?2 Take the fictional case of 31-year-old Ms Alvarez, who, since age 18, has had many clearly recognizable episodes of depression that last a week or more. When asked, she endorses phases of increased activity and remarkable productivity; increased social interaction; and a confident, positive outlook that is otherwise unusual for her—all on about 4 to 5 hours of sleep. She does not endorse increased energy during these phases, however.
Does she have bipolar II? According to DSM-IV, she might qualify (barring other diagnoses that trump bipolar disorder, such as a mood disorder due to a general medical condition). But because she does not endorse increased energy phases, she does not quite reach a diagnosis of bipolar II according to DSM-5. Will this tighter requirement increase diagnostic accuracy?
Intuitively, the answer seems obvious: surely the harder it is for a patient to meet all the diagnostic requirements, the harder it should be to award a diagnosis of bipolar disorder. Yet surprisingly, if we look at the statistical determinants of diagnostic accuracy, tighter criteria will have little impact. The reward for working through the following review of these statistical determinants is the understanding that the greatest impact of diagnostic accuracy comes from clinicians, not from tightening criteria.
1. American Psychiatric Association. DSM-5 Development. http://www.dsm5.org. Accessed March 11, 2013.
2. Mitchell PB. Bipolar disorder: the shift to overdiagnosis. Can J Psychiatry. 2012;57:659-665.
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9. The “Bipolarity Index.” http://www.psycheducation.org/depression/STEPBipolarityIndex.htm. Accessed March 11, 2013.
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11. Zaratiegui RM, Vázquez GH, Lorenzo LS, et al. Sensitivity and specificity of the mood disorder questionnaire and the bipolar spectrum diagnostic scale in Argentinean patients with mood disorders. J Affect Disord. 2011;132:445-449.
12. Screening for Bipolarity: MoodCheck. http://www.psycheducation.org/PCP/launch/downloadMoodCheck.htm. Accessed March 11, 2013.