Objectives: To establish the psychometric characteristics of the Patient Heath Questionnaire (PHQ) (PHQ-2, -9, and their sequential administration) in older adults who use community-based, social service care management.
Design: Comparison of screening tools with criterion standard diagnostic interview.
Setting: A community-based aging services agency.
Participants: Three hundred seventy-eight adults aged 60 years or older undergoing in-home aging services care management assessments.
Measurements: Subjects were administered the PHQ-9 and Structured Clinical Interview for DSM-IV-TR- fourth edition. The authors examined the sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios, and receiver operating characteristic (ROC) curve for the PHQ-2 and PHQ-9 separately, and for a two-stage screening process that used each in sequence (the PHQ-2/9).
Results: Using a cut score of 3, the sensitivity of the PHQ-2 was 0.80 and the specificity was 0.78. The area under the ROC curve (AUC) for the PHQ-2 was 0.87. Using a cut score of 10, the sensitivity and specificity of the PHQ-9 were 0.82 and 0.87. The AUC was 0.91. The sensitivity and specificity of the two-stage PHQ-2/9 were 0.81 and 0.89, respectively, and the AUC was 0.91.
Conclusions: The greater specificity of the PHQ-9 is an advantage over the PHQ-2 in aging service settings in which false-positive tests have potentially high cost. The PHQ-2/9 performed equally well as the PHQ-9, but would be more efficient for the agency to administer. Combined with an appropriate referral system to healthcare providers, use of the PHQ-2/9 sequence by aging services personnel can efficiently assist in reducing the burden of late-life depression.