1. ¹Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
2. ²Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
3. ³New York State Psychiatric Institute and the Department of Psychiatry, College of Physicians and Surgeons of Columbia University, New York, NY, USA
4. ⁴Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
5. ⁵Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
6. ⁶Emory University School of Medicine, Atlanta, GA, USA
7. ⁷Department of Psychiatry, University of Arizona College of Medicine, Tucson, AZ, USA
8. ⁸American Psychiatric Institute for Research and Education and Division of Research at the American Psychiatric Association, Arlington, VA, USA
9. ⁹Department of Psychology, Vanderbilt University, Nashville, TN, USA
10. ¹⁰Department of Psychiatry, Vanderbilt University, Nashville, TN, USA
11. ¹¹Department of Pharmacology, Vanderbilt University, Nashville, TN, USA

Correspondence: Dr AJ Rush, Department of Psychiatry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9086, USA. Tel: +1 214 648 4601; Fax: +1 214 648 4612; E-mail: john.rush@utsouthwestern.edu

Received 5 May 2005; Revised 9 May 2006; Accepted 15 May 2006; Published online 21 June 2006.

Abstract

This report summarizes recommendations from the ACNP Task Force on the conceptualization of remission and its implications for defining recovery, relapse, recurrence, and response for clinical investigators and practicing clinicians. Given the strong implications of remission for better function and a better prognosis, remission is a valid, clinically relevant end point for both practitioners and investigators. Not all depressed patients, however, will reach remission. Response is a less desirable primary outcome in trials because it depends highly on the initial (often single) baseline measure of symptom severity. It is recommended that remission be ascribed after 3 consecutive weeks during which minimal symptom status (absence of both sadness and reduced interest/pleasure along with the presence of fewer than three of the remaining seven DSM-IV-TR diagnostic criterion symptoms) is maintained. Once achieved, remission can only be lost if followed by a relapse. Recovery is ascribed after at least 4 months following the onset of remission, during which a relapse has not occurred. Recovery, once achieved, can only be lost if followed by a recurrence. Day-to-day functioning and quality of life are important secondary end points, but they were not included in the proposed definitions of response, remission, recovery, relapse, or recurrence. These recommendations suggest that symptom ratings that measure all nine criterion symptom domains to define a major depressive episode are preferred as they provide a more certain ascertainment of remission. These recommendations were based largely on logic, the need for internal consistency, and clinical experience owing to the lack of empirical evidence to test these concepts. Research to evaluate these recommendations empirically is needed.