Bipolar and Depressive Disorders in Diagnostic and Statistical Manual of Mental Disorders-5: Clinical Implications of Revisions from Diagnostic and Statistical Manual of Mental Disorders-IV

Byline: Rajiv. Tandon Introduction Our modern system of classifying and diagnosing psychiatric disorders originated in Emil Kraepelin's dichotomization between dementia praecox (schizophrenia) and manic-depressive insanity (bipolar and unipolar disorders). Since that time, there have been separate sections on psychotic disorders and mood disorders in both the International Classification of Diseases (ICD) and Diagnostic and Statistical Manual of mental disorders-5 (DSM-5) diagnostic manuals. This dichotomy has increasingly been called into question [sup][1],[2] and genetic, other neurobiological, and pharmacological data suggest that bipolar disorders may be on a continuum between schizophrenia and unipolar depression. [sup][2],[3] In addition, the definitions of these disorders in DSM-IV present a number of problems in clinical practice, including high use of not otherwise specified (NOS) diagnoses, high rates of spurious comorbidity, unclear boundaries with schizoaffective disorder, discrepant treatment of catatonia, and poor explanation of the significant heterogeneity within each diagnostic category. DSM-5 [sup][4] sought to address these limitations and incorporate new knowledge about these conditions generated over the past 20 years. Changes in the section on psychotic disorders were summarized in a prior issue of the Journal. [sup][5] Some of those changes relevant to the clinical description of the mood disorders include a single set of criteria to diagnose catatonia and its treatment as a specifier across all disorders [sup][6],[7] and more stringent criteria for schizoaffective disorder. [sup][8],[9],[10] In this article, we address the major changes made in the mood disorders section in DSM-5. Separation of Bipolar Disorders from Depressive Disorders One of the major changes made in DSM-5 is the division of the mood disorders section into two units, one on bipolar and related disorders and the other on depressive disorders. [sup][11] The unit on bipolar and related disorders is placed in between the section on schizophrenia spectrum and other psychotic disorders on the one side and the section on depressive disorders on the other. A conglomerate of genetic and neurobiological findings supports this intermediate position of bipolar disorder between schizophrenia and unipolar depression. Whereas bipolar depression shares clinical features with unipolar depression (depressive symptoms, tendency toward an episodic course, family history, comorbidities), bipolar disorder also shares significant features with schizophrenia (symptomatology, genetic markers, family history, response of mania to antipsychotic agents). [sup][2],[3],[12],[13],[14] This lends support to the change made in DSM-5 and is also consistent with observations that neurocognitive deficits and various neurobiological findings are seen across the spectrum of psychotic disorders, spanning schizophrenia through bipolar disorder to major depression. [sup][15],[16] Although there is much empirical support and sound rationale for this separation between bipolar and depressive (unipolar) disorders, it has been criticized [sup][17] because it conflicts with Kraepelinian orthodoxy. [sup][18] Since DSM-5 has also been criticized for being too conservative in its approach, [sup][19] this illustrates the challenges in updating our system of psychiatric classification. [sup][20] Whereas the research implications of this change are evident, placement of bipolar and related disorders and unipolar and related disorders in separate chapters reinforces the clinical imperative of recognizing important differences between bipolar and unipolar depression with regard to comorbidities, treatment, and outcome. Bipolar and Related Disorders Five relatively modest changes were made in an effort to improve clinical utility and specificity in the diagnosis of bipolar and related disorders. These include: *The elimination of the category of bipolar disorder, mixed, and its replacement by a new specifier "with mixed features"; *Addition of a requirement that abnormal and persistently increased goal-directed activity or energy accompany elated or irritable mood as an essential criterion (criterion A) for diagnosing mania or hypomania; *Addition of "anxious distress" and other specifiers to improve the precision of characterizing these disorders in a clinically pertinent manner; *Provision of specific criteria for defining sub-threshold bipolar disorders; and *Elimination of antidepressant medication as an exclusion criterion for diagnosing mania or hypomania. …