The impact of treatment decisions on the diagnosis of bipolar disorders

Editorial The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) has broadened the criteria for specified bipolar disorders with the introduction of the diagnostic category of ‘other specified bipolar and related disorders’ (DSM-5: 296.89). In a prior editorial, we critically discussed how the way we diagnose bipolar disorders may impact treatment decisions, especially for patients with newly specified subthreshold bipolar II disorder (full depressive episode plus a hypomanic episode that does not meet the duration or number of symptoms required for a full episode) (Frances and Jones 2012; Phillips and Kupfer 2013; Severus and Bauer 2013; Zimmerman 2012; Angst 2013). In this editorial, we will examine how treatment decisions may, in turn, impact the diagnosis of bipolar disorders. Specifically, we will focus on how acute and prophylactic treatment of subthreshold bipolar II disorder may impact the rate of conversion to a diagnosis of bipolar I disorder. In the DSM-5, subtypes of the nonorganic bipolar disorders are differentiated primarily by the number, duration, and intensity of the manic symptoms, as summarized in Table 1. To illustrate how the treatment of subthreshold bipolar II disorder may impact diagnosis, we will consider the case of a young patient with a history of a major depressive episode who visits his psychiatrist. Starting abruptly over the last 2 days, the patient felt increasingly ‘hyper’ and energetic despite sleeping less than usual and had a fierce argument with his girlfriend. On close scrutiny, it turned out that the patient's history is also positive for a single past episode of short-duration hypomania, but negative for hypomanic or manic episodes, use of antidepressants, other substance use, and medical comorbidities (Do and Mezuk 2013). However, his father suffers from severe bipolar I disorder. The patient is exhibiting a prototype hypomanic syndrome (DeFife et al. 2013), meets the DSM-5 criteria for ‘short-duration