Aims: The aim of this study was to determine if chronic pain patients with symptoms of depression could be identified by one single question.
Methods: Data from 595 patients, 55% women, and 45% men, from three different patient populations; low back pain patients (n = 387), whiplash patients (n = 119), and disability pensioners (n = 89), were analysed. We evaluated the test characteristics of one question on depression from the Subjective Health Complaints (SHC) Inventory. The respondents report if, and to what extent, they have been affected by sadness/depression in the last 30 days. The Hopkins Symptom Checklist-25 (HSCL-25) was used as the criterion standard. HSCL-25 is a self-report symptom rating scale with two dimensions: depression and anxiety. ''Depressed'' was defined as having a score above 1.75 on the depression subscale.
Results: Thirty-three per cent of the patients were depressed according to HSCL-25. The sensitivity of the single SHC depression-question was 79%, and the specificity was 81%. Positive predictive value was 67% while negative predictive value was 89%. Kappa value for all groups combined was 0.58 (p < 0.001). The receiver operating characteristic (ROC) curve showed an area under the curve of 0.83.
Conclusions: The depression-question from SHC identified most of the depressed patients measured by HSCL-25 in low back pain patients, whiplash patients, and disability pensioners, and can therefore be considered an indicator of depression. Satisfactory sensitivity and specificity were detected, as well as similar responsiveness as determined by the ROC analyses. The results indicate that one simple question could replace a whole questionnaire (HSCL-25) in identifying depressive patients.