Letters to the Editor
Reply: Cade’s Disease and Beyond
Dear Editor:
Dr Wiebe describes 2 cases that in our opinion fail to indicate that bipolar disorder (BD) is overdiagnosed. In the first case, a patient was diagnosed with BD and spent a great deal of time on Internet chat sites, to the dismay of her family. This activity does not speak at all to the question of whether the BD diagnosis was accurate. In the second case, the patient was diagnosed with BD and did not feel that valproate helped her. Again, this fact by itself does not prove that the BD diagnosis was inaccurate. Indeed, response to a single mood stabilizer occurs, at best, in only one-third of patients with BD (1). Many patients with BD who respond to lithium do not respond to valproate, and vice versa (2). The correspondent’s complaint in the second case appears chiefly to be about the treatments for BD and not about the diagnosis itself. It is our sense that many clinicians hesitate to diagnose BD because of their dissatisfaction with available treatments. This is a practical problem; hopefully, it will be less of an issue as newer, more tolerable mood stabilizers are developed. However, this practical problem has nothing to do with the empirical fact of whether someone meets or does not meet criteria for BD, based on an accurate and complete examination of symptoms and history. It is also interesting that both patients apparently responded poorly to standard unipolar treatments (antidepressants), yet the author does not conclude that this argues against the unipolar diagnosis. In fact, poor outcomes with antidepressants are quite common in the histories of patients with BD, as we reviewed in our paper.
We therefore just do not see how these 2 cases at all justify a claim for overdiagnosis of BD. We agree that there are cases in which BD is erroneously diagnosed. Possibly, the vague use of the term “mood swings” may lead to a mistaken diagnosis of BD in a person with a personality disorder or some other condition. However, in our paper, we described much more specific criteria than vague mood swings.
Importantly, to our knowledge there is absolutely no published or presented empirical evidence supporting the idea that BD is overdiagnosed. There is, as we reviewed in our paper, plenty of evidence to the contrary—that BD has been and remains underdiagnosed. Even if occasional cases of erroneous diagnosis were found, it would be necessary to show that such cases are more frequent than the misdiagnosis of BD before one could claim that BD overall is overdiagnosed. It is a simple fact of scientific method, highlighted by the evidence-based medicine literature (3), that case reports do not refute empirical studies. There is no appreciable evidence that BD is overdiagnosed.
References
1. Denicoff KD, Smith-Jackson EE, Disney ER, Ali SO, Leverich GS, Post RM. Comparative prophylactic efficacy of lithium, carbamazepine, and the combination in bipolar disorder. J Clin Psychiatry 1997;58:470–8.
2. Bowden CL, Brugger AM, Swann AC, Calabrese JR, Janicak RG, Petty F, and others. Efficacy of divalproex vs lithium and placebo in the treatment of mania. JAMA 1994;271:918–24.
3. Gray GE. Evidence-based medicine: an introduction for psychiatrists. Journal of Psychiatric Practice 2002;8:5–13.
S Nassir Ghaemi, MD
James Y Ko, AB
Frederick K Goodwin, MD
Cambridge, Massachusetts
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