Five out of 100 Koreans suffer from depression and the prevalence of the disease has rapidly risen almost by two folds in recent 10 years, a study by Asan Medical Center showed.

The study outcome is significant because it was based on large-scale big data of more than one million people, the hospital said.

The research team, led by Professors Shin Yong-wook and Jo Min-woo at the Psychiatry Department at AMC, said they used the National Health Insurance Service’s sample cohort data that randomly extracted clinical data of over a million patients regardless of age among patients who received treatment from 2002 to 2013. Then, the team analyzed the prevalence of depression and the relationship between depression and suicide.

The researchers found that the prevalence of patients suffering from depressive disorder nearly doubled to about 5.3 percent in 2013 from 2.8 percent in 2002.

“Until now, the prevalence of depression in Korea had been reported to be about 3 percent, which was lower than around 5 percent of advanced countries,” the research team said. “However, in reality, the depression prevalence was found to be similar to that of advanced countries.”

By gender, the study found that about 3.9 and 6.8 percent of men and women suffer from depression, indicating that women are at higher risk of depression.

The team confirmed that the prevalence also increased with age.

More specifically, people over the age of 80 had the highest proportion of patients suffering from depression, with 18.4 percent, followed by 13.9 percent among those in their 60s and 70s, 5.7 percent in 40s and 50s, and 2.7 percent in 20s and 30s.

The team also said that depression directly affects the suicide rate. Depressed people have an approximately four times higher suicide risk than healthy people.

The research team also analyzed the suicide rate according to sex, age, income level, and residence area, which are known as factors related to suicide.

The researchers found that males or older people had a higher suicide risk of about 2.5 and 1.5 times, respectively, than females or younger people.

However, the team noted that income level and residence area had nothing to do with suicide rates.

“The proportion of patients newly diagnosed with depression compared to the entire sample group was similar each year,” Professor Cho said. “However, the overall prevalence rate continued to increase, indicating that if depression is not treated well, it could become chronic.”

Shin also said, “If anyone feels that their daily life is difficult due to depression, they should seek medical help as soon as possible.”

Scientific Reports recently published the results of the study.