Diagnosis of Bipolar Disorders: Focus on Bipolar Disorder I and Bipolar Disorder II

Charles L. Bowden, MD

In This Article

Abstract and Introduction

Bipolar disorders are currently divided into 4 entities: bipolar I, bipolar II, cyclothymic disorder, and bipolar disorder not otherwise specified, as described in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV).[1] These subtypes of bipolar disorders cover a spectrum of severities, frequencies, and durations of manic and depressive symptoms. The differential diagnosis among these and with regard to other disorders with similar symptom features remains the foundation for treatment of bipolar disorders. It is clear that much diversity exists within these major subtypes, such that designations like "rapid cycling" and "bipolar III" are being put forward and probed for clinical relevance. Some of the concerns and advantages of including these less-established manifestations of bipolar disorders in our diagnostic thinking are discussed here, and the utility and drawbacks of our current diagnostic protocols are considered.

There has been increasing recognition that the population of patients with bipolar features to their mood disorders can exhibit a wide variation in the severity of manic and depressive episodes, as well as in the frequency of cycling between such episodes. This has inspired efforts to further characterize subtypes of bipolar disorders and to scrutinize mood disorders generally for links between unipolar and bipolar disease. For example, while most clinical studies of patients with atypical depression (most recent depressive episode with features of mood reactivity/overreactivity to positive events, hyperphagia, hypersomnolence, severe fatigue/leaden paralysis, chronic oversensitivity to rejection) have excluded patients with definite bipolar disorder, many patients who fit this depressive symptomatology indeed have features of bipolar II disorder.[2] This ongoing probing of variation within well-established mood-disorder entities promises, eventually, to benefit patients through identifying the most effective treatments for each specific subtype. It also aids in evaluating the outcomes of such treatments and offers the hope of discovering prognostic markers. The need for diagnostic, if not academic, distinction between bipolar and other disorders, such as between a manic episode of bipolar I disorder and attention-deficit/hyperactivity disorder (ADHD), is increasing as well. Heightened attention to the latter has generated an increased tendency to medicate children for ADHD that may have outpaced the practitioners' ability to reliably distinguish this disorder from a bipolar condition.


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