Speaking a more consistent language when discussing severe depression: a calibration study of 3 self-report measures...

We recently found marked disparities between 3 self-report scales that assess the DSM-IV criteria for major depressive disorder in the percentage of depressed outpatients considered to have severe depression. The goal of the present report from the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project was to calibrate the measures against a clinician-rated criterion standard and to establish a cutoff point on each scale that identifies a similar prevalence of severe depression and increases the level of agreement between the scales in identifying severe depression.

353 depressed outpatients (DSM-IV) completed the Clinically Useful Depression Outcome Scale, Quick Inventory of Depressive Symptomatology, and Patient Health Questionnaire from June 2010 to January 2013. The patients were also rated on the 17-item Hamilton Depression Rating Scale (HDRS). The goal of the analyses was to identify the cutoff point on each of the self-report scales that would identify a prevalence of severe depression similar to that identified by the HDRS (defined as a score of 25 and above).

On the basis of the scale developers' recommended cutoffs, the prevalence of severe depression varied greatly (range, 15.3%-67.4%), and the level of agreement between the pairs of scales was low. After calibration, the self-report scales identified a similar percentage of patients as severely depressed (range, 22.2%-26.5%), and the level of agreement between the scales in identifying severe depression increased.

If clinicians are to follow treatment guidelines' recommendations to base initial treatment selection, in part, on depression severity, then it is important to have a consistent method of determining depression severity. The present calibration study of 3 self-report depression questionnaires identified cutoff scores that resulted in similar prevalence rates of severe depression and increased the level of agreement between the scales.