Psychometric properties of the Patient Health Questionnaire nine-item version (PHQ-9) for use among hospitalized non-psychiatric medical patients

Abstract

Background: Depression comorbid with non-psychiatric illness is widely prevalent, and the source of considerable burden. Reliable rating tools to detect depression in the general medical setting are therefore needed across different regions, including Argentina. The present study aimed to compare the psychometric characteristics of the Patient Health Questionnaire 9 (PHQ-9), Beck Depression Inventory-II (BDI-II) and Hospital Anxiety and Depression Scale (HADS) against each other, using independent criterion for the diagnosis of a major depressive episode (MDE).Methods: A multicenter, cross-sectional study was conducted over six months, screening 257 hospitalized general medical patients across three hospitals. After admission, participants were interviewed by a trained psychiatrist using the Mini International Neuropsychiatric Interview (MINI), and then each participant went through the administration of PHQ-9, BDI-II, and HADS.Results: For the diagnosis of a MDE according to the MINI, the best cut-off scores were 10 for the PHQ-9, 16 for the BDI-II, and 15 for the HADS. Owing to clinical interpretability issues, a two-factor solution was preferred using exploratory factor analysis (component 1 ?somatic/neurovegetative?, and component 2 ?psychological/cognitive? of depression). The local version of the PHQ-9 had high internal consistency (Cronbach's alpha=.87). Conclusions: The Argentine version of the PHQ-9 questionnaire showed acceptable validity and reliability for the screening of depressive symptoms.