Reliability of the retrospective Clinical Interview Schedule Revised (rCIS-R) to assess relapse in depression in primary care patients

Objectives: We are not aware of a simple and short structured measure that retrospectively assesses time to relapse for depression. We developed the retrospective Clinical Interview Schedule Revised (rCIS-R) to assess depression relapse in the previous 12 weeks, for use in a clinical trial of maintenance antidepressant treatment. We assessed test-retest reliability and construct validity in relation to a Global Rating Question (GRQ) about worsening mood, participants stopping their study medication and Patient Health Questionnaire (PHQ‐9) scores. Methods: In our study 444 participants provided data for rCIS-R, GRQ and PHQ-9 and 396 participants completed rCIS-R on two occasions about 30 minutes apart. The reliability study was nested within a randomised controlled trial (ANTLER). Results: We found substantial test-retest agreement for the rCIS-R definition of relapse (kappa 0.84 (95%CI 0.71 to 0.97)), for individual sections and timing of relapse (Intraclass Correlation Coefficient 0.94 (95%CI 0.92 to 0.95)). Comparison of relapse with GRQ, stopping study medication and PHQ-9 supported the construct validity of the rCIS-R. Conclusions: The rCIS-R provides a reliable way of assessing relapse of depression over the previous 12 weeks. Its brevity, self-report format, simplicity of scoring and absence of training requirement makes it attractive to use in randomised controlled trials.