Making clinicians lives easier: guidance on use of the QIDS self-report in place of the MADRS.

BACKGROUND

The ability to convert total scores from one scale to another facilitates the interpretation of research findings and facilitates the use of systematic measurement in clinical practice.

METHODS

Item Response Theory methods were used to convert total scores between the 16-item Quick Inventory of Depressive Symptomatology (QIDS-SR16) and the Montgomery Asberg Depression Rating Scale (MADRS) total scores. Data were obtained from a sample of 233 outpatients with highly treatment-resistant, nonpsychotic major depressive episodes participating in a one-year open label study of vagus nerve stimulation to augment psychotropic medication treatment.

RESULTS

MADRS total scores averaged 31.9 (SD = 6.7) at baseline and 21.9 (SD = 11.0) at one year. QIDS-SR16 total scores averaged 17.6 (SD = 3.6) at baseline and 12.5 (SD = 5.8) at one year. Based on one-year data (or exit if the patient did not complete one year), corresponding QIDS-SR16 and MADRS total scores were presented for each possible QIDS-SR16 and MADRS total score. A QIDS-SR16 total score of 5 was comparable to a MADRS total score of 7 or 8 (7.5).

LIMITATION

The degree to which these results generalize to less treatment-resistant samples is unknown.

CONCLUSION

The conversion of QIDS-SR16 and MADRS total scores provides a basis for clinicians who wish to use the QIDS-SR16 to understand what MADRS total scores reported in clinical trials approximate QIDS-SR16 total scores obtained with their patients.