Definitions of antidepressant treatment response, remission, nonresponse, partial response, and other relevant outcomes: A focus on treatment-resistant depression

Multiple definitions have been used to characterize the outcome of treatmen ts for depression. Beyond the simple criterion of a statistically significa nt improvement in depression rating scale scores, researchers have had to u se more clinically relevant categorical outcomes: response (without remissi on), remission, nonresponse, partial response, relapse, recurrence, recover y, and, more recently, depressive breakthrough. This article reviews the de finitions of these terms and their relevance for the study of treatment-res istant depression.