A brief clinical tool to estimate individual patients' risk of depressive relapse following remission: Proof of concept

Abstract

Objective: The authors sought to determine whether symptoms experienced by formerly depressed patients after at least 8 weeks of remission can be used to identify their risk for relapse during the next 6 months. Method: The study included 188 patients with major depressive disorder from the National Institute of Mental Health Collaborative Depression Study who had at least one Symptom Checklist-90 (SCL-90) assessment after at least 8 weeks of full remission from a depressive episode (defined as a value of 1 on the weekly psychiatric rating scale for all depressive conditions, recorded on Longitudinal Follow-Up Evaluation interviews). Mixed logistic regression was used to identify a set of SCL-90 items that were most predictive of relapse compared with nonrelapse within the next 6 months. Results: Of 514 SCL-90 assessments completed after remission, 73 (14.2%) were followed by depressive relapse within 6 months. Seventeen SCL-90 items (including symptoms of depression, anxiety, and psychological vulnerability) significantly distinguished relapse from nonrelapse. Of these, a set of 12 symptoms maximally separated relapse from nonrelapse. Experiencing one or more of these symptoms had a sensitivity of 80.8% and a specificity of 51.2% for identifying a period in which a relapse occurred, with a positive predictive value of 21.5% and a negative predictive value of 94.2%. The relapse rate was 5.8% when none of the 12 symptoms were present, 16.4% when one to five symptoms were present, 34.1% when six to nine symptoms were present, and 72.7%when10 ormore symptoms were present. Conclusions: A brief symptom scale can be used to identify patients who, despite full remission from a depressive episode, are at substantial risk of relapse within the next 6 months, and this can be used to provide a basis for personalizing the intensity of follow-up visits.