Psychometric properties of the Quick Inventory of Depressive Symptomatology (QIDS-SR) in UK primary care

Abstract It is widely believed that severity of depressive disorder should guide treatment selection and many guidelines emphasise this factor. The Quick Inventory of Depressive Symptomatology (QID-SR16 ) is a self-complete measure of depression severity which includes all DSM-IV criterion symptoms for major depressive disorder. The object of this study was to assess the psychometric properties of the QIDS-SR16 in a primary care sample. Adult primary care patients completed the QIDS-SR16 and were assessed by a psychiatrist (blind to QIDS-SR16 ) with the 17-item Hamilton Rating Scale for Depression (GRID-HAMD). Internal consistency, homogeneity and convergent and discriminant validity of the QIDS-SR16 were assessed. Severity cut-off scores for QIDS-SR16 were assessed for convergence with HRSD-17 cut-offs. Published methods for converting scores to HRSD-17 were also assessed. Two hundred and eighty-six patients participated: mean age = 49.5 (s.d. = 13.8), 68% female, mean HRSD-17 = 12.6 (s.d. = 7.6). The QIDS-SR16 exhibited acceptable internal consistency (Cronbach's alpha = 0.86), a robust factor structure indicating one underlying dimension and correlated highly with the HRSD-17 ( r = 0.79) but differed significantly in how it categorised the severity of depression relative to the HRSD-17 (Wilcoxon Signed Rank Test p