Background: Late-life experiences such as protracted and indisposing medical disorders can negatively impact older adults' psychological and mental health, making them vulnerable to depression. Majority of the assessment tools for depression were developed for use in western countries. There is therefore the need for availability of culture- and environment-specific tools for assessment of depression in low-and-middle-income countries. This study was designed to cross-culturally adapt and validate the Geriatric Depression Scale-15 (GDS-15) into Igbo language and culture.

Methods: The English version of the GDS-15 was translated into Igbo language; synthesized, back-translated, and underwent expert panel review, pretesting and cognitive debriefing interview, according to the American Academy of Orthopedic Surgeons' guidelines. The Igbo version of the GDS-15 was tested for concurrent and structural validities, and internal consistency among consecutively recruited 140 consenting older adults (62.9% females) in Enugu North Senatorial District at 0.05 level of significance.

Results: The English version of the GDS-15 was successfully cross-culturally adapted to Igbo with all the 15 items still retained on the Igbo version of the GDS-15. The Igbo version of the GDS-15 exhibited the same structure as the English version, and displayed a Cronbach's alpha value of 0.53 with no significant ceiling (0%) and floor (0%) effects. The correlation between the participants' total scores on the Igbo and the English versions of the GDS-15 (ρ = 0.86) was adequate. There was no significant difference between corresponding scores in the English and Igbo versions of the GDS-15 (p = 0.89).

Conclusions: The Igbo version of the GDS-15 is a valid and culturally specific instrument, and can be used for assessing depression among Igbo older adults in Nigeria.