Brief self-rated screening for depression on the Internet

Abstract

Background: The Internet offers promising possibilities for the quick screening of depression for treatment and research purposes. This paper aims to validate three self-rated measures to screen for depression on the Internet: SID (single-item depression scale), CES-D (Center for Epidemiological Studies Depression scale) and K10 (Kessler psychological distress scale).

Methods: Of the 502 subjects aged 18-80 who rated the SID, CES-D and K10 measures on the Internet, 157 (31%) subjects were also interviewed by telephone using the WHO Composite International Diagnostic Interview (C)IDI) for DSM-IV-disorders.

Results: Cronbach's alpha for both web self-rated measures CES-D and K10 was 0.90. The SID correlated 0.68 (P<0.001) with the CES-D and with the K10. The CES-D correlated 0.84 with the K10 (P<0.001). Subjects with a DSM-IV diagnosis for any depressive disorder had significantly higher means (P<0.001) on the three self-rated measures for depressive symptoms than subjects without a diagnosis of any depressive disorder. Using any depressive disorder as the gold standard, the area under the curve (AUC) of the SID was 0.71 (95% CI: 0.63-0.79), which was significantly lower than the AUC of the CES-D (AUC: 0.84; 95% CI: 0.77-0.90, P=0.003) and of the K10 (AUC: 0.81; 95% CI: 0.73-0.88, P=0.0024). The AUCs for the K10 and CES-D did not differ significantly from each other.

Limitations: The CIDI interviews were not recorded, so inter-rater reliability could not be calculated.

Conclusions: The CES-D and K10 are reliable, valid tools for care providers to quickly screen depressive patients on the Internet and for researchers to collect data.