The number of Koreans diagnosed with panic disorder surged 44 percent last year from 2017, with experts suggesting growing social and psychological stress as a possible cause.

According to a report released by the National Health Insurance Service on Thursday, a total of 200,540 people received hospital treatment for panic disorder in 2021, up 44.5 percent from 138,726 in 2017.

Of them, males accounted for about 45 percent or 89,273, while the number of female patients stood at 111,267.

The 2021 figures show that panic disorders occurred more frequently in the elderly than in the younger generation, indicating that older people aged over 40 were more prone to depression and illness.

Patients in their 40s accounted for the biggest proportion, at 23.4 percent of the total patients, followed by 50-somethings at 19.2 percent and 30-somethings at 18.3 percent, the figure showed. Patients in their 20s and 30s accounted for 2.7 and 15.7 percent, respectively.

The state-run agency defined panic disorder as an anxiety disorder of a person abruptly experiencing periods of intense fear or a feeling that something bad may occur.

The cost of treating anxiety also jumped from 49.6 billion ($37.6 million) to 91 billion won -- doubling in just four years. The data showed that 40-somethings accounted for the biggest share of this, at 22.7 billion won.

Professor Park Jae-sub at NHIS Ilsan Hospital said panic disorder often begins in early adulthood, explaining why most patients were in their 40s. Park also advised people to get treatment early if they feel panic disorder-like symptoms.