The State of Knowledge of Chronic Depression

Abstract

The Definition of Chronic Depression Dr. Gelenberg: Let’s begin with a discussion of the definition of chronic depression. What is the clinical relevance of the subtypes of depression in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV)? Dr. McCullough: My colleagues and I have reported on 1316 patients with chronic depression. We found no differences when a wide variety of demographic, psychosocial, and health measures were compared. For the DSM-V, we have argued that the existing subtypes do not represent qualitatively distinct entities. We have recommended a 2-by-2 table to accommodate a 4-fold classification of the unipolar disorders: mild versus moderate-to-severe severity and acute versus chronic types of episodes (Table 1). We can greatly simplify the current subtypes of chronic depression by consolidating them into a single category termed chronic depression. Dr. Gelenberg: Will you define chronic depression? Dr. McCullough: Chronic depression lasts a minimum of 2 years without at least a 2-month hiatus or a full remission. We are not suggesting the elimination of the DSM-IV categories for depressive disorders, but are recommending the deletion of distinct chronic subtypes since these subtypes do not represent qualitatively different entities. Dr. Ninan: Perhaps we should review the current diagnostic criteria for depressive disorders. The criteria for dysthymia require depressed mood for the majority of time and 2 additional symptoms that persist for 2 years, while the criteria for a major depressive episode stipulate 5 or more symptoms, including depressed mood or anhedonia, persisting for at least 2 weeks. Dysthymia followed by a major depressive episode is frequently labeled double depression. In the DSM-IV, chronic depression is defined as the persistence of the full criteria for a major depressive episode for at least 2 years. Major depressive disorder with incomplete recovery occurs when enough symptoms improve that the patient no longer meets the full criteria for major depressive disorder, but still has residual symptoms of depression (i.e., subsyndromal depression). If that patient later meets the full criteria for a major depressive episode without a period of remission in between, we consider it another episode of major depression (i.e., 2 episodes with incomplete recovery in between). Dr. McCullough: On our 2-by-2 table, we recommend maintaining dysthymia on the chronic row and in the mild severity column. Most of the disorders that Dr. Ninan just delineated would be in the moderateto-severe column. On the acute episode row, the mild disorder would be labeled minor depressive disorder and the moderate-to-severe episode would be termed episodic major depression. Dan N. Klein, Ph.D., has LEADING EXPERTS IN THE TREATMENT