Why do adults get depressed? The role of in utero malnutrition and son-preference

Purpose: The fetal origins hypothesis suggests that a focus on the prenatal period is driven by evidence that adult health can be shaped during fetal development. From a life-course perspective, we investigate the impact of early childhood malnutrition on depression symptoms in middle-aged adults. Methods: Utilizing data from the China Health and Retirement Longitudinal Study (CHARLS), we apply a combination of cohort difference in differences (DID) and instrumental variables (IV) methods to determine the causal effects. Our analysis also explores the son-preference culture in effects heterogeneity. Results: Our study results robustly indicate that exposure to malnutrition in utero exacerbates adult depression symptoms and suggests that the son-preference culture contributes to gender-related health disparities. Conclusions: These findings underscore the importance of implementing timely and appropriate screening and intervention policies during early life to improve mental health outcomes in adulthood.