Impact of response shift effects in the assessment of self-reported depression during treatment: Insights from a rTMS versus Venlafaxine randomized controlled trial

Purpose: Patient-Reported Outcomes are essential to properly assess treatment effectiveness in randomized clinical trial (RCT) for Major Depressive Disorder (MDD). MDD self-assessment may vary over time depending on change in the meaning of patients' self-evaluation of depression, i.e. Response Shift (RS). Our aim was to investigate RS and its impact on different depression domains in a clinical trial comparing rTMS versus Venlafaxine.Methods: The occurrence and type of RS was determined using Structural Equation Modeling applied to change over time in 3 domains (Sad Mood, Performance Impairment, Negative Self-Reference) of the short-form Beck Depression Inventory (BDI-13) in a secondary analysis of a RCT on 170 patients with MDD treated by rTMS, venlafaxine or both.Results: RS was evidenced in the venlafaxine group in the Negative Self-Reference and Sad Mood domains.Conclusion: RS effects differed between treatment arms in self-reported depression domains in patients with MDD. Ignoring RS would have led to a slight underestimation of depression improvement, depending on treatment group. Further investigations of RS and advancing new methods are needed to better inform decision making based on Patient-Reported Outcomes.

Automated summary

The study aims to investigate the essentiality of Patient-Reported Outcomes in evaluating treatment effectiveness for Major Depressive Disorder (MDD) in randomized clinical trials. The study finds that self-assessment of MDD may change over time due to patients' interpretation of depression, known as Response Shift (RS). It also reveals that RS has different effects on self-reported depression domains depending on the treatment arms.