Prevalence of major depressive disorder in the general population of South Korea

Introduction: Previous epidemiological studies have reported a high prevalence of major depressive disorder (MDD) in North America and Western Europe. However, little information exists on MDD in Asian countries. This study investigates the prevalence of MDD and its characteristics in the general population of South Korea. Methods: A representative sample of the South Korean general population composed of 3719 non-institutionalized individuals aged 15 years or older was interviewed by telephone using the Sleep-EVAL system. The participation rate was 91.4%. The interviews covered sociodemographic characteristics, health care utilization, physical illnesses and Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) psychiatric disorders. Results: A depressive mood, i.e., feeling sad, downcast, having the blues or having lost interest in things formerly pleasant was reported by 20.9% of the sample without significant difference between men and women and among age groups. DSM-IV MDD was found in 3.6% (95% CI: 3.0-4.2%) of the sample. The prevalence of MDD was comparable among age groups. Shift workers were more likely to have MDD than daytime workers. Factor significantly associated with MDD were: being a woman, being a light or heavy smoker, perceiving one's health as being average or poor, doing physical activities at least three times per week in the evening, having a BMI below 18.5 kg/m² and perceiving one's life as being moderately or highly stressful. Conclusions: Prevalence of MDD in Korea is higher than what it was previously estimated to be two decades ago. The number of individuals seeking help for depression was very low, and only a small number of MDD subjects received appropriate treatment for their condition.