Attention Deficit Hyperactivity Disorder, a behavioral condition, is becoming increasingly prevalent in South Korea, data showed on Thursday.

Statistics from the National Health Insurance Corporation show that the number of people diagnosed with ADHD has doubled over the last four years in the nation, rising from 53,056 in 2017 to 102,322 in 2021.

Among the total number of patients, teenagers accounted for 41.3 percent (42,265), followed by of children under the age of 9 at 22.3 percent (24,331), and people in their 20s at 21.6 percent (22,132). The disorder affects males 2.4 times more than females.

“Most of the patients are diagnosed with ADHD after entering elementary school, so there are many teenage patients compared to other age groups,” said Ahn Jae-eun, a professor at Ilsan Hospital, a facility run by the National Health Insurance Corporation.

ADHD is characterized by a short attention span, excessive activity or difficulty controlling behavior, sometimes resulting in poor school performance. Not paying attention in class, getting bored with school assignments, continuously moving, getting distracted and blurting out inappropriate comments are the typical symptoms of ADHD.

The cause of most ADHD cases is unknown but is believed to be inherited or involve interactions between genetics, the environment and social factors. It is also speculated that it may sometimes be caused by brain injuries, smoking and drinking during pregnancy, or exposure to lead.

About 60 percent of patients suffer from the disorder until they reach adulthood, while 40 percent are successfully treated. If proper treatment is not provided, symptoms can cause difficulties in various areas of life, such as interpersonal problems or difficulties with financial management.