The Effects of Higher Education on Midlife Depression: Quasi-Experimental Evidence from South Korea

Higher education has expanded worldwide, with women outpacing men in many regions. While educational attainment is consistently linked to better physical health, its mental health effects - particularly for women - remain underexplored, and causal evidence is limited. We estimate the impact of college completion on depression among middle-aged women in South Korea, leveraging the 1993 higher education reform, which raised women's college attainment by 45 percentage points (pp) over the following decade. We use two nationally representative datasets to triangulate evidence, including the Korea National Health and Nutrition Examination Survey (KNHANES, 2007-2021) for physician-diagnosed depression, and the Korean Longitudinal Survey of Women and Families (KLoWF, 2007-2022) to validate findings using self-reports of depressive symptoms. We implement two-stage least squares (2SLS) with a birth-cohort instrument based on exposure to the reform (within 3 years of the cutoff in KNHANES and within 1 to 3 years in KLoWF). In KNHANES, college completion lowers physician-diagnosed depression by 2.4 pp, attenuating to 1.6 pp after adjusting for income, employment, and physical health. In KLoWF, college completion improves self-reported mental health. The weekly depressive-symptoms composite declines by 17.4 pp, attenuating to 16.4 pp after covariate adjustment. Placebo tests on unaffected cohorts yield null results. This study contributes to the growing quasi-experimental literature on education and mental health with convergent evidence across clinical diagnoses and self-reported depressive symptoms in South Korea. By focusing on college education in a non-Western setting, it extends the external validity of existing findings and highlights educational policy as a potential lever to reduce the burden of midlife depression among women.