Comparison of Depression-related Factors among Young Adults Pre- and Post-COVID-19: Focusing on the Early Pandemic Period

Objectives: This study aimed to compare the prevalence and influencing factors of depression among young adults before and during the COVID-19 pandemic, based on Pender’s Health Promotion Model as the theoretical framework. Methods: Data were drawn from the Korea National Health and Nutrition Examination Survey (KNHANES) 2018 and 2020. The sample comprised 2,147 young adults aged 19-34 years (2018: n=1,091; 2020: n=1,056). Depression was defined as a Patient Health Questionnaire-9 (PHQ-9) score of ≥10. Complex-sample analyses with stratification, clustering, and weighting were applied. Group differences were examined using Rao–Scott χ²-tests, and predictors of depression were identified through logistic regression. Results: Depression prevalence rose from 5.3% in 2018 to 8.1% in 2020 (p=0.022). Before the pandemic, significant factors included sex, stress, sleep duration, subjective health status, health-related quality of life (HRQOL), high-risk drinking, and economic activity. During the pandemic, significant factors were low education, chronic disease, stress, short sleep, poor subjective health, low HRQOL, suicide planning, smoking, and lack of economic activity. Stress, inadequate or excessive sleep, poor subjective health, low HRQOL, and unemployment were consistently related to depression across both periods. High-risk drinking was significant only before the pandemic, while low education and suicide planning emerged as new risk factors afterward. Conclusions: Depression among young adults increased significantly during the COVID-19 pandemic, with shifts in related factors. Pender’s model highlighted the interplay of personal, cognitive–affective, and social participation factors, emphasizing the need for tailored interventions and policy support to promote mental health.