Validación y utilidad de la encuesta PHQ-9 (Patient Health Questionnaire) en el diagnóstico de depresión en pacientes usuarios de atención primaria en Chile

background: depressive disorders (td) is a set of prevalent diseases that require proper diagnosis and treatment. in chile, the instruments of evaluation and diagnosis are scarce. as a way to address this difficulty, the objective of this study was to validate the spanish version of the self-reported patient health questionarie (phq-9), the consulting population in primary care in chile. the phq-9 to detect depressive symptoms as mild, moderate or severe, and has proven to be an efficient diagnostic tool. methods: 1327 patients evaluated in june 2005 from five urban general practices of the commune of valdivia answered individually the phq-9. a subsample was compared with the hamilton scale for depression, icd-10 criteria for depression and xx version of the phq-9. results: the phq-9 demonstrated a sensitivity of 92% and 89% specificity in detecting depressive patients, when compared to the hamilton-d scale. it presents a construct validity and predictive validity concurrent with the icd-10 criteria for depression. conclusions: the phq-9 showed a psychometric allowing clinical use in primary care patients in chile.