Self-report and clinician-rated measures of depression severity: can one replace the other?

Background: It has been suggested that clinician-rated scales and self-report questionnaires may be interchangeable in the measurement of depression severity, but it has not been tested whether clinically significant information is lost when assessment is restricted to either clinician-rated or self-report instruments. The aim of this study is to test whether self-report provides information relevant to short-term treatment outcomes that is not captured by clinician-rating and vice versa.

Methods: In genome-based drugs for depression (GENDEP), 811 patients with major depressive disorder treated with escitalopram or nortriptyline were assessed with the clinician-rated Montgomery-Åsberg Depression Rating Scale (MADRS), Hamilton Rating Scale for Depression (HRSD), and the self-report Beck Depression Inventory (BDI). In sequenced treatment alternatives to relieve depression (STAR*D), 4,041 patients treated with citalopram were assessed with the clinician-rated and self-report versions of the Quick Inventory of Depressive Symptomatology (QIDS-C and QIDS-SR) in addition to HRSD.

Results: In GENDEP, baseline BDI significantly predicted outcome on MADRS/HRSD after adjusting for baseline MADRS/HRSD, explaining additional 3 to 4% of variation in the clinician-rated outcomes (both P < .001). Likewise, each clinician-rated scale significantly predicted outcome on BDI after adjusting for baseline BDI and explained additional 1% of variance in the self-reported outcome (both P < .001). The results were confirmed in STAR*D, where self-report and clinician-rated versions of the same instrument each uniquely contributed to the prediction of treatment outcome.

Conclusions: Complete assessment of depression should include both clinician-rated scales and self-reported measures.