Development and psychometric evaluation of a Persian version of the Death Depression Scale-Revised: a cross-cultural adaptation for patients with advanced cancer

Objective: The surfacing of thoughts and depressive affect associated with the prospect of death are prevalent among patients with advanced cancer. Because death cognitions and associated negative affect occur along an adaptive-less adaptive continuum, it is essential that valid and reliable instruments are available to measure death depression. The present study aimed to determine the psychometric properties of the Death Depression Scale among Iranian patients with advanced cancer.

Methods: About 497 cancer patients completed a Persian version of the 21-item Death Depression Scale-Revised. The face, content and construct validity of the scale were ascertained. Reliability was also assessed using internal consistency, construct reliability and intra-class correlation coefficient (ICC).

Results: Construct validity determined one factor with an eigenvalue greater than 1. The model had a good fit (χ2 (179, N = 248) = 520.345, P < 0.001; χ2/df = 2.907, CFI = 0.916, TLI = 0.902, IFI = 0.917, SRMR = 0.049 and RMSEA = 0.088 (90% confidence interval = 0.079-0.097)) with all factors loadings greater than 0.5 and statistically significant. The internal consistency, construct reliability and ICC were greater than 0.70. Convergent validity of the scale was demonstrated.

Conclusions: Findings revealed that the Persian version of the Death Depression Scale-Revised is valid and reliable, and may be used to assess and evaluate death depression in Iranian patients with advanced cancer.