Comparison of the Personal Health Questionnaire and the Self Reporting Questionnaire in rural Pakistan.

OBJECTIVE To apply ROC analysis to select the best threshold scores for the PHQ and SRQ; to compare the sensitivity and specificity of the PHQ and SRQ against a criterion diagnosis of depressive disorder in a community sample in rural Pakistan, and to examine the influence of socio-demographic factors on misclassification. METHODS The study used a two-stage design. Receiver Operating Characteristic (ROC) analysis was used to estimate the optimal threshold score and to compare the ability of the Self Reporting Questionnaire (SRQ) and the Personal Health Questionnaire (PHQ) to discriminate between cases of depressive disorder and non-cases. RESULTS The results of the ROC analysis suggest that the SRQ is superior to the PHQ, and at the threshold of 5/6, the SRQ has superior sensitivity, negative predictive value and percentage agreement compared with the PHQ. When the SRQ threshold is raised it gains specificity, and at a cut-off threshold of 7/8 it is superior to the PHQ (5/6) in all validity coefficients and percentage agreement. Only gender and the presence of a confidant had a significant effect on misclassification using the SRQ among the cases. Both questionnaires performed better for females based on comparison of the areas under the ROC curves. CONCLUSION This study has demonstrated that the Urdu translations of both the PHQ and SRQ can be used as screening tests for depressive disorder in the Pakistani population. People with little or no education answer both somatic and psychological items with equal ease. Inconclusion, the PHQ does not appear to have any advantage over the SRQ.