The number of North Korean defectors settling in South Korea has grown rapidly since the mid-1990s, when North Korea’s food shortage problem worsened significantly. The cumulative number of North Korean defectors who had entered South Korea was approximately 1,000 in 2002, and it exceeded 10,000 by February 2007; by March 2016, the number had grown to 29,137 [1]. As the number of North Korean defectors settling in South Korea continues to increase, there is heightened interest in their ability to adapt to South Korean society [2].

The South Korean government has implemented a variety of supportive policies, such as the Act for the Protection and Settlement Support of North Korean Defectors (enacted on April 14, 1997), to ensure that North Korean defectors living in South Korea can be self-reliant and self-sufficient. In 2012, the South Korean government expanded its resettlement facilities for North Korean defectors (named ‘The 2nd Hana Won’), strengthened its special education programs for female defectors, and increased efforts to support the psychological stability and health of North Korean refugees. Additionally, the Ministry of Labor, in collaboration with private businesses and companies, launched the ‘Job Creation Project for North Korean Defectors’ program to address the employment problems that defectors cite as their greatest challenge. In September 27, 2010, the Act for the Protection and Settlement Support of North Korean Defectors was revised to encompass the Foundation for Supporting North Korean Defectors and the North Korean defector preparatory school scheme and to provide greater support for securing employment [1].

Despite these continuing efforts at the national level, North Korean defectors, particularly the absolute poor, continue to struggle with social adjustment and mental illnesses. The mental illnesses in this population are primarily associated with the actual process of defection and the period of residence in a third country. In the mid-1990s, when there were still relatively few defectors, China accepted some refugees in response to the food shortages in North Korea. However, as the number of North Korean defectors grew over a prolonged period, China altered its position and began to repatriate the defectors [3,4]. This forced repatriation made settling in China an uncomfortable process, rendering North Korean defectors psychologically vulnerable due to the threat to their basic rights.

The psychological effects of the persistent and complex traumatic experiences of North Korean defectors account for 29.5% of all post-traumatic stress disorder (PTSD) cases in this population [5]. PTSD is a chronically relapsing condition characterized by the avoidance of places and behaviors related to the trauma and by symptoms (e.g., hyperactivity) that can manifest after stressful events (e.g., car accidents, wars, natural disasters, and rape) involving serious physical injury. The vivid traumatic experiences that characterize defection from North Korea, such as human rights abuses, family breakups, beatings, violence, imprisonment, and starvation, represent the main causes of PTSD [6].

Among the various stressors experienced by North Korean defectors, the fear of trafficking is the most frequently cited (by 83.4% of defectors) [7]. In total, 56% of North Korean defectors residing in China and 9.2% under the care of Chinese protection agencies reported suffering from PTSD [8,9]. Based on consultations with 133 defectors residing in South Korea, Doctors Without Borders reported that 18.2% of North Korean refugees experienced difficulties due to PTSD [8-11]. In general, the psychological impact of defection increases an individual's vulnerability to future stressors, thereby constituting a sustained and persistent effect [10,12].

In many cases, PTSD causes somatic symptoms that result in both physical and mental illnesses. A survey conducted using the Patient Health Questionnaire-15 (PHQ-15) to measure somatization among North Korean defectors showed that this population tended to experience more somatic symptoms than the general South Korean population [13]. Physical illnesses increase medical service use, which, in turn, increases total medical costs. The presence of PTSD among North Korean defectors increases care-related expenditures at both the societal and the individual levels. Thus, the effects of PTSD go beyond the suffering of those who actually have this condition and should be managed in a wider socio-economic context.

The purpose of this study was to investigate the rate of PTSD among North Korean defectors by examining the medical records of refugees who visited the National Medical Center, Seoul, Korea over a period of approximately 10 years and to examine patterns of medical service use according to the presence of PTSD. This study also aimed to contribute to the development of a systematic mental health care system designed specifically for North Korean defectors and to clarify the current mental health status of this group in preparation for any future unification of Korea.

The average age of the North Korean defectors was 38.8 years; 23.8% were male, and 76.2% were female. The large majority of defectors (98.4%) were medical benefits recipients, and 15.5% of this group used neuropsychiatry treatment. The average number of visits was 14.7, and the average revenue per visit was 48.2 USD.

Among those defectors who visited the Psychiatry Department, 83.7% were female and 96.8% received medical benefits. The average number of visits was 37.1, and the average revenue per visit for psychiatry was 39.3 USD (Table 1).

The average number of visits was 41.8 among PTSD patients, and it was 33.2 among patients without PTSD. The revenue was 953.6 USD among PTSD sufferers, and it was 231.1 USD among those without PTSD (Table 2).

Data on the average number of visits by North Korean defectors and the total revenue of all National Medical Center departments were evaluated according to PTSD status. Regression analysis showed a correlation between the presence of PTSD and the average number of outpatient visits and between the presence of PTSD and the total revenue of all National Medical Center departments (Table 3).

The purpose of this study was to use EMR data to investigate the prevalence of PTSD among North Korean defectors who visited the National Medical Center over a period of approximately 10 years and to examine the different patterns of medical service usage according to the presence of PTSD.

Among refugees who visited the Psychiatry Department, those with a primary diagnosis of PTSD used psychiatric services more frequently than those without PTSD. In particular, the total revenue of patients with PTSD was almost three times higher than of those without PTSD, and the total revenue of the Psychiatry Department was also higher of patients with PTSD than of those without PTSD. Previous studies have demonstrated increased rates of medical service usage among patients with a diagnosis of PTSD [14].

The high rate of medical service usage among North Korean defectors diagnosed with PTSD is due to the presence of somatic symptoms that result in both physical and mental illnesses. PTSD is associated with increased psychiatric morbidity, medical utilization and costs [15-17]. Mental illnesses, including PTSD, can increase vulnerability to physical ailments. A cross-sectional study investigating severely traumatized defectors and asylum seekers residing in Switzerland found that severity of PTSD symptoms was significantly associated with somatization and explosive anger [18]. Another cross-sectional study of defectors residing in Norway who were in outpatient psychiatric treatment and who had experienced traumatic events found that chronic clinically significant pain was present in 66% of all the patients and in 88% of those with a current PTSD diagnosis. The most common locations of chronic pain were the head (80%), chest (74%), arms/legs (66%), and back (62%), and females had significantly more chronic pain sites than men. Comorbid PTSD and chronic pain was seen in 57% of the outpatients [19]. Other studies have shown that PTSD sufferers tend to be more likely to report nonspecific somatic complaints than those without PTSD [20-22], even when there are no differences in the physical and laboratory test results of the two groups [23,24].

High rates of physical illness lead to increased medical service use, which, in turn, is directly linked to higher medical costs. Therefore, the presence of PTSD increases the likelihood of medical service usage. PTSD can no longer be considered a burden only to individuals; it also represents a socioeconomic problem at the societal level. According to the North Korean Defectors Survey, 38.3% of North Korean refugees expressed a desire for medical support; this constituted their second-highest priority, after only economic support [25]. In this study, only 15.5% of North Korean defectors visited the Psychiatry Department, but 45.2% of those had a diagnosis of PTSD. In several studies, the prevalence of PTSD among North Korean refugees in the community was about 0% [5,7,26]. The PTSD rate among the defectors in this study may have been higher because they were psychiatry outpatients. Considering the relatively high PTSD prevalence of North Korean Defectors in South Korea (1.5%), a health care plan targeting this population is required [27].

Because the majority of North Korean defectors are diagnosed with PTSD due to serious trauma experienced during their escape, approaches to managing the mental health of this group that focus on PTSD should be a top priority. In policy terms, we believe that well-defined and precisely targeted researches and strategies are required to determine the mental health status of North Korean defectors, especially those with a diagnosis of PTSD, and to reduce the cost of their medical care. Ultimately, the social ‘safety net’ must be widened to improve the short-term mental health of North Korean defectors as well to reduce their long-term medical costs.

This study had several limitations. First, the study population was not representative of all North Korean defectors, as it relied only on the medical records of defectors who visited the National Medical Center. However, it is representative of those who visited the medical institution that treated the most North Korean defectors in South Korea and that established a specialized refugee treatment center. Second, the reliability of medical records or diagnosis could be biased in this population because this is a retrospective study using medical record. Third, this study did not consider certain factors associated with PTSD and other mental health conditions due to a lack of available data. However, socioeconomic factors, such as income and educational level, have been associated with PTSD and medical service use rates [2,28]. Fourth, this study did not measure the severity of PTSD, which may have varied significantly among patients. Fifth, North Korean defectors who did not visit the National Medical Center were not evaluated. North Koran defectors who do not visit a hospital but nevertheless suffer from severe PTSD may differ from those who do present at medical facilities.

Despite its limitations, this study closely examined the relationship between PTSD status (present or absent) and the rate of medical service usage by reference to the EMRs of North Korean defectors who visited the National Medical Center. The majority of the defectors visited the Psychiatry Department, and those with a diagnosis of PTSD had a higher average number of outpatient visits and higher total revenue. Additionally, such patients used a greater number of medical services. Additionally, when South Korea and North Korea are unified in the future, medical usage and expenses are expected to increase exponentially. Therefore, it is necessary to estimate the cost of medical treatment considering North Korean defectors’ medical usage. This study implies that North Korean defectors with PTSD diagnose have higher medical expenditure than those who were not diagnosed. Considering the high medical expenses of North Korean defectors residing in South Korea, further investigations should examine differences in medical service use patterns according to PTSD status.