Objective

. To translate and culturally adapt the Patient Health Questionnaire (PHQ-9) to three varieties of Quechua and analyse their validity, reliability, and measurement invariance.

Materials and methods

. 1) Cultural adaptation phase: the PHQ-9 was translated from English into three variants of Quechua (Central, Chanca, Cuzco-Collao) and translated again into English. Then, experts and focus groups allowed the translations to be culturally adapted. 2) Psychometric phase: the unidimensionality of the adapted PHQ-9 was evaluated by using Confirmatory Factor Analysis (CFA), reliability was evaluated by internal consistency (Alpha and Omega), and measurement invariance according to Quechua varieties and sociodemographic variables was evaluated by using CFA, multigroups and MIMIC models (Multiple Indicator Multiple Cause).

Results

. Each of the adaptations of the PHQ-9 to the three Quechua varieties reported clear and culturally equivalent items. Subsequently, data from 970 Quechua-speaking adult men and women were analyzed. The general one-dimensional model reported an adequate fit (Comparative fit index = 0.990, Tucker-Lewis index = 0.987, Standardized root mean squared residual= 0.048, Root mean squared error of approximation=0.071); each of the Quechua varieties also showed an adequate fit. Reliability was high for all varieties (α = 0.865 - 0.915; ω = 0.833 - 0.881). The results of the multigroup CFA and MIMIC models confirmed measurement invariance according to Quechua variant, sex, residence, age, marital status and educational level.

Conclusions

. The PHQ-9 adaptations to Central Quechua, Chanca and Cuzco-Collao offer a valid, reliable and invariant measurement, confirming that comparisons can be made between the evaluated groups. Its use will benefit mental health research and care for Quechua-speaking populations.

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