“Cade's Disease” and Beyond: Misdiagnosis, Antidepressant Use, and a Proposed Definition for Bipolar Spectrum Disorder

Abstract

The diagnosis and treatment of bipolar disorder (BD) has been in con sis tent and frequently mis under stood in re cent years. To identify the causes of this problem and suggest possible solutions, we under took a critical review of studies concerning the nosology of BD and the effects of antidepressant agents. Both the under diagnosis of BD and its frequent mis diagnosis as unipolar major depressive dis order (MDD) appear to be problems in patients with BD. Under diagnosis results from clinicians' in adequate under standing of manic symptoms, from patients' im paired in sight into mania, and especially from failure to involve family members or third parties in the di agnostic process. Some, but by no means all, of the under diagnosis problem may also result from lack of agreement about the breadth of the bipolar spectrum, beyond classic type I manic-depressive illness (what Ketter has termed “Cade's Dis ease”). To alleviate confusion about the less classic varieties of bipolar illness, we propose a heuristic definition, “bipolar spectrum disorder.” This diagnosis would give greater weight to family history and antidepressant-induced manic symptoms and would apply to non-type I or II bipolar illness, in which depressive symptom, course, and treatment response character is tics are more typical of bipolar than unipolar illness. The role of antidepressants is also controversial. Our review of the evidence leads us to conclude that there should be less emphasis on using antidepressants to treat per sons with this illness.