Screening for depression in primary care: will one or two items suffice?

Small differences in implementation of screening and the associated burden on clinicians and patients could have substantial effects on the sustainability of screening in routine primary care. Therefore, we investigated the psychometric properties of single items and two-item combinations of the "WHO-5 Well Being Index" (WHO-5) and compared the obtained characteristics to those of the original version as well as to another proposed two-item screener (developed from PRIME-MD and BPHQ, respectively). Screening and diagnostic interview data from 431 primary care patients were analysed. Main outcome measures were sensitivity, specificity and AUC values. All test characteristics were assessed using the diagnoses derived from the Composite International Diagnostic Interview (CIDI) as the criterion standard.Single-item screening questions proved rather inadequate. However, only marginal differences in performance were found between two questions and the longer screening instrument with respect to major depression, dysthymia and "any depressive disorder". There were no statistically significant differences between these AUC values and most other test characteristics assessed. The results suggest that screening could be reduced to two questions with a potential advantage in terms of ease of administration and scoring and decreased staff and patient burden and perhaps a reduced stigma associated with a positive screening score.