Trends in the prevalence and treatment of bipolar affective disorder in South Korea.

This study aimed to assess trends in the prevalence of bipolar disorder (BP). We also analyzed patterns of medical use by Korean patients with BP, defined as those diagnosed with the International Classification of Diseases (ICD) F31 code who used at least one inpatient or outpatient medical service in a year. We analyzed yearly BP prevalence and inpatient hospitalization periods per year from 2008 to 2017 using National Health Insurance Service (NHIS) claims data for 52.43 million people. Overall, the BP prevalence was 0.2 %, as of 2017, with consistently higher rates in women. The BP prevalence was highest among those aged ≥60 years (0.27 %) and was lowest among those aged 0-29 years (0.12 %), as of 2017. The average annual rate of increase among those aged 0-29 years and ≥60 years was 8.48 % and 7.39 %, respectively, which exceeded the overall mean of 6.58 %. The average annual rate of increase in BP prevalence for those aged 30-59 years was 4.67 %. The proportion of inpatients who were hospitalized for longer than 180 days decreased, while the proportion of those hospitalized for 0-14 days increased. The estimated BP prevalence was higher when using the most recent NHIS data rather than in the surveys. These prevalence rates can be used to support the development of future mental health policies.