The 16-item Quick Inventory of Depressive Symptomatology (QIDS), clinician rating (QIDS-C), and self-report (QIDS-SR): A psychometric evaluation in patients with chronic major depression

Background: The 16-item Quick Inventory of Depressive Symptomatology (QIDS), a new measure of depressive symptom severity, derived from the 30-item Inventory of Depressive Symptomatology (IDS), is available in both self-report (QIDS-SR16) and clinician-rated (QIDS-C-16) formats. Methods: This report evaluates and compares the psychometric properties of the QIDS-SR16 in relation to the IDS-SR30 and the 24-item Hamilton Rating Scale for Depression (HAM-D-24) in 596 adult outpatients treated for chronic nonpsychotic, major depressive disorder. Results: Internal consistency was high for the QIDS-SR16 (Cronbach's alpha=.86), the IDS-SR30 (Cronbach's alpha=.92), and the HAM-D-24 (Cronbach's alpha=.88). QIDS-SR16 total scores were highly correlated with IDS-SR30 (.96) and HAM-D-24 (.86) total scores. Item-total correlations revealed that several similar items were highly correlated with both QIDS-SR16 and IDS-SR30 total scores. Roughly 1.3 times the QIDS-SR16 total score is predictive of the HAM-D-17 (17-item version of the HAM-D) total score. Conclusions: The QIDS-SR16 was as sensitive to symptom change as the IDS-SR30 and HAM-D-24, indicating high concurrent validity for all three scales. The QIDS-SR16 has highly acceptable psychometric properties, which supports the usefulness of this brief rating of depressive symptom severity in both clinical and research settings.