Primary care Screening Questionnaire for Depression: reliability and validity of a new four-item tool

BACKGROUND: Unidentified depression in primary care is a public health concern, globally. There is a need for brief, valid and easily administered tools in primary care. AIMS: To estimate reliability and validity of the newly developed Primary care Screening Questionnaire for Depression (PSQ4D), a four-item tool, with ‘yes’ or ‘no’ options. METHOD: PSQ4D was administered verbally (time required, <1 min) by primary care physicians to adult outpatients (n=827) in six primary care settings in Kerala, India. A psychiatrist evaluated each patient on the same day, using ICD-10 Diagnostic Criteria for Research, based on unstructured clinical interview. RESULTS: The Cronbach’s alpha for internal consistency reliability was 0.80; kappa coefficient for test–retest reliability was 0.9 and that for interrater reliability was 0.72. At a score ≥2, sensitivity was 0.96, specificity was 0.87, positive predictive value was 0.74, negative predictive value was 0.98, positive likelihood ratio was 7.4 and negative likelihood ratio was 0.05. CONCLUSIONS: When physician administered, PSQ4D has good reliability. At a cut-off score of ≥2, it has high sensitivity and specificity to identify depressive disorder in primary care. DECLARATION OF INTEREST: None. COPYRIGHT AND USAGE: © The Royal College of Psychiatrists 2017. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license.