Depression and fitness: the Portuguese-Brazilian version of the evolutionary fitness scale

Abstract

The concept of fitness is crucial to the study of human behavior from an evolutionary perspective. A proposed causal link between fitness-related problems and depression has been suggested. Measuring fitness in humans requires exploring behavioral components, such as mating, parental investment, social capital, and health-oriented actions. This study navigates the relationship between depression and fitness, exploring the validity of the Evolutionary Fitness Scale in the Brazilian context. A sample of 804 Brazilian participants completed the EFS online. Exploratory Factor Analysis suggested a 4-factor model. Internal consistency was good (partner α = 0.87; health α = 0.80; social capital α = 0.85; offspring α = 0.74). The EFS differentiated between nondepressed and depressed individuals based on PHQ-9 scores, with a large effect size for health (d = 0.93) and social capital (d = 0.89) dimensions, and a medium effect for partner (d = 0.40). However, the offspring subscale did not discriminate between depressed and nondepressed. In summary, we demonstrated that the EFS represents an efficient, reliable, and valid measure for assessing self-reported data on human fitness.