Factorial invariance of the Spanish version of the PHQ-9 by gender and country in Latin America and the Caribbean

Introduction: Depression is one of the leading causes of global disease burden, particularly in regions with high inequality such as Latin America and the Caribbean (LAC). The Patient Health Questionnaire-9 (PHQ-9) is one of the most widely used instruments internationally for screening depressive symptoms, although its structural validity and diagnostic comparability in LAC still require further evidence. Objective: To examine the factorial structure, invariance by sex and country, internal consistency, and concurrent validity of the PHQ-9 in a multinational sample of Latin American adults. Method: Data from 12,124 participants across 15 LAC countries were analyzed, collected through an online form using snowball sampling. Confirmatory factor analysis (CFA) and multigroup invariance analysis were applied, along with Omega coefficient and correlations with GAD-7 and Mini-Z. Results: The PHQ-9 showed a unidimensional structure with excellent fit (CFI = .989; RMSEA = .075), adequate internal consistency (Ω = .89), and evidence of configural, metric, scalar, and strict invariance by sex and country. High correlation with GAD-7 (r = .79) and moderate correlation with Mini-Z (r = .64) supported its concurrent validity. Conclusion: The PHQ-9 demonstrated robust psychometric properties and diagnostic comparability across countries and sexes in LAC. These findings reinforce its utility as a standardized and culturally adaptable tool for screening depressive symptoms in clinical and community settings in the region.