The Quick Inventory of Depressive Symptomatology, Self-Report (QIDS-SR16): a Psychometric Evaluation in Patients With Asthma and Major Depression

Statement of the Problem: Despite research evidence of high comorbidity between depression and asthma, few studies have addressed the performance of assessment tools which may assist physicians in assessing depression among asthma patients. The present study is the first to evaluate the psychometric properties of the self-report Quick Inventory of Depressive Symptomatology (QIDS-SR16), a 16-item measure of depressive symptom severity, in asthma patients. Methods: The psychometric properties of the QIDS-SR16 are compared and evaluated in relation to the self-report Inventory of Depressive Symptomatology (IDS-SR30) and the17- item, clinician-rated Hamilton Rating Scale for Depression (HRSD17) in 73 asthma outpatients treated for nonpsychotic Major Depressive Disorder. Correlations between the depression rating scales and the Mini Asthma Quality of Life Questionnaire (MiniAQLQ) were calculated. Results: Internal consistency at exit was strong for the QIDS-SR16 (Cronbach's a =.87) and the IDS-SR30 (Cronbach's a =.95). Total scores for the QIDS-SR16 showed high correlations with the HRSD17 (.85) and the IDS-SR30 (.97) total scores. One-hundred percent of the QIDS-SR16 items and 93% of the IDS-SR30 item-total score correlations reached statistical significance of p<.0001. The QIDS-SR16, the IDS-SR30, and the HRSD17 showed comparable sensitivity to symptom change, indicating high concurrent validity for all three scales. The total QIDS-SR16 baseline to exit change score demonstrated a significant negative correlation to the MiniAQLQ, providing another indicator of concurrent validity. Conclusions: The QIDS-SR16 shows good reliability and impressive construct validity, including test homogeneity, content validity, and concurrent validity. Strong psychometric properties as well as a self-report format, brief administration time, and sensitivity to treatment change make the QIDS-SR16 a valuable clinical and research instrument.