Validation and utility of the patient health questionnaire in diagnosing mental disorders in 1003 general hospital Spanish inpatients

Objective: To determine whether the Spanish version of the patient health questionnaire (PHQ) has validity and utility for diagnosing mental disorders in general hospital inpatients. Methods: Participants in the study were 1003 general hospital inpatients, randomly selected from all admissions over an 18-month period. All of them completed the PHQ, the Beck Depression Inventory (BDI), and measures of functional status, disability days, and health care use, including length of hospital stay. They also had a structured interview with a mental health professional. Results: A total of 416 (42%) of the 1003 general hospital inpatients had a PHQ diagnosis. There was good agreement between PHQ diagnoses and those of an independent mental health professional (for the diagnosis of any PHQ disorder, kappa = 0.74; overall accuracy, 88%; sensitivity, 87%; specificity, 88%), similar to the original English version of the PHQ in primary care patients. Patients with PHQ diagnoses had more functional impairment, disability days, and health care use than did patients without PHQ diagnoses (group main effects for functional status measures and disability days, kappa < .001; group main effects for health care use, p < .01). The group main effect for hospital length of stay was not significant. An index of depression symptom severity calculated from the PHQ correlated significantly both with the number of depressive symptoms detected at interview and the total BDI score. PHQ administration was well accepted by patients. Conclusions: The Spanish version of the PHQ has diagnostic validity in general hospital inpatients comparable to the original English version in primary care.