The number of bipolar disorder patients in South Korea has surged in recent years, a survey showed on Sunday.

According to data released by the National Health Insurance Service, the number of patients who received hospital treatment for bipolar disorder grew by 26 percent, or 12,000, over five years. Some 46,000 patients were found to have the mental illness in 2007, whereas the number climbed to 58,000 in 2011.

Medical expenses for bipolar disorder treatment also increased from 55 billion won ($48.6 million) to 77 billion won over the same period.

The rise of manic depression patients in their late 20s was significant as they face the most extreme form of stress while starting out in the workforce.

Work-related stress, including fierce competition at work and underemployment, was found to be the main reason for the increasing number of bipolar patients in Korea, the report said.

Bipolar disorder is a type of mood disorder in which patients usually experience severe mood swings. Some experience insomnia and have difficulties making decisions due to their impulsive and erratic behavior.

The increase in bipolar disorder among females in their 20s was 10.2 percent per year on average, and 9.6 percent among the males in the same age group, according to the data.

By Kwon Bum-joon
(bjkwon@heraldcorp.com)