Suicide is one of the most common causes of death worldwide and contributes significantly to the global public health cost (1). The World Health Organization (WHO) estimated nearly 800,000 deaths due to suicide in 2016 (2). Intentional self-harm was reported as the most common cause of death under age 70 in South Korea in 2016 (3). South Korea reported the highest suicide rate among the Organization for Economic Cooperation and Development (OECD) countries in 2017, which was 23 per 100,000 South Koreans who died by suicide (2). Medical expenses for individuals who died by suicide in the year before their deaths, and productivity losses from premature deaths were estimated at 3.85 trillion won per year in South Korea (4). Meanwhile, previous suicide attempts are one of the biggest predictors of suicide deaths (5). Around 40% of those who died by suicide have a history of at least one previous attempt (6). Those who had a previous suicide attempt are 12–30% more likely to re-attempt suicide. In addition, there is a higher risk of death by suicide in the first 1–3-years after the initial suicide attempt (7, 8). Therefore, interventions that prevent repeat suicidal behaviors after a suicide attempt are important. There have been studies reporting the benefits of interventions to reduce suicide re-attempts including emergency psychiatric consultation, brief psychotherapeutic interventions, community based case management, and active contact and follow-up interventions using letters/postcards, text messaging, and/or telephone calls (9–11).

For 10–24-years old, defined as “young people” by the WHO (12), suicide is one of the common causes of death (13, 14). According to the WHO definition, young people include both adolescents (10–19-years old) and youth (15–24-years old) (12, 15). Suicide in adolescence consequently reduces the age group of social production, which can adversely affect not only social losses, but also national development. Therefore, early intervention to prevent suicides is necessary (16). A number of results have been published showing differences in the reasons for and methods of suicide attempts between adults and adolescents. Adults often attempt suicide because of psychiatric illnesses, but adolescents are often affected by emotional factors, such as anger, frustration, and rejection in interpersonal relationships (17, 18). Adolescents often seem to choose suicide attempts impulsively as a means of avoiding psychological conflict or expressing extreme pain (19, 20).

Recently, the importance of a crisis intervention system that helps suicide attempters return to everyday life through early management has been emphasized (21). In several countries, various systems are in place, including the operation of special emergency rooms for treating suicide attempters (22, 23). Early detection and management systems for high-risk patients with mental problems in a medical setting, including use of a medical-psychiatry unit or emergency-psychiatry unit, can shorten the duration of hospital stays by reducing delays in psychiatric consultation (21, 22). Therefore, the Ministry of Health and Welfare and the Central Suicide Prevention Center have been operating a project called the “Post-management Service for Suicide Attempters in the Emergency Room” in regional emergency medical centers since 2013.

Taking these into account, a multi-disciplinary emergency consultation system (MECS) for suicide attempters with a drug overdose was established in our hospital. We targeted patients presenting with a drug overdose because it is the most common method of suicide attempt in South Korea (24). The purpose of this study was to compare the characteristics of suicide attempts by drug overdose between young people (10–24-years old) and adults, and evaluate the cost-effectiveness of the MECS for suicide attempters with a drug overdose. We hypothesized that young suicide attempters would tend to have factors associated with more unplanned (impulsive) suicide attempts than planned ones. We also hypothesized that the MECS would reduce unnecessary treatment cost, especially for non-serious unplanned attempts.

So far, there have been several cross-sectional studies using the data from the “Post-management Service for Suicide Attempters in the Emergency Room” project (25–29), but few longitudinal studies have been conducted on the effectiveness of post-management services for suicide attempters. Results from the current study show that young people used more painkillers for suicide attempts and had more unplanned attempts than planned ones as compared to the adults. A comparison before and after the MECS implementation revealed that the MECS system was cost-effective, especially for young and non-serious suicide attempters.

In this study, there were differences in the types of drugs used for suicide attempts in young people and adults. Use of painkillers accounted for a higher percentage in young people than in adults, whereas adults tended to use psychoactive medications and lethal drugs, such as herbicides or pesticides. More lethal drug use in adults is in line with results from previous studies, which have reported that patients tend to take deadly drugs for suicide attempts as they get older (30, 31). Another potential reason for the high use of psychoactive drugs in adults is that they may have more access to drugs than teenagers who are under the supervision their parents or caregivers and are limited to psychiatric treatments per their guardian's decisions. There are several possible reasons for the higher use of painkillers among young people compared to adults. Adolescents often find it difficult to get psychiatric treatment, even if they want to, because of stigma about mental health held by their parents (32). Therefore, the availability of psychoactive drugs may be limited for adolescents, which could explain their reasons for choosing more easily accessible drugs like painkillers. Since November 2012, the Ministry of Health and Welfare has implemented a safety-based drug system that allows for the sale of medications, such as painkillers, to increase public access to medication at convenience stores (33). Since then, painkillers have become relatively easy to obtain in South Korea without a prescription (33). Therefore, adolescents may have tended to use over-the-counter drugs instead of psychiatric medications (34).

In this study, young people had a higher rate of unplanned suicide attempts than planned ones, and a lower percentage of intentional suicide attempts than adults, which could be attributed to several factors. According to previous studies, adults often attempt suicide because of psychiatric illnesses, but adolescents are often affected by emotional factors, such as anger, frustration, and rejection in interpersonal relationships (17, 18). Adolescents tend to choose suicide as a means of expressing extreme pain because of emotional factors rather than attempting suicide because they really want to die (19, 20, 35). In fact, adolescents find it difficult to control negative feelings caused by interpersonal problems in family or peer relationships and are likely to engage in non-suicidal self-injury (36). Adolescents are also influenced by the media to a great extent and may imitate celebrity suicides (37, 38). Difficulty with impulse control and immature decision-making processes could also make them vulnerable to internal confusion and external influences, often leading to more unplanned impulsive suicide attempts than planned ones (39). Neurobiologically, this may be related to a lack of sufficient development in the decision-making areas of the brain. The process of controlling impulsiveness and decision-making is deeply related to several parts of the brain, in particular, the pre-frontal cortex (40). The frontal lobe plays an important role in controlling hazardous behavior in relation to various areas of the brain, such as the dorsolateral pre-frontal cortex and the posterior mesofrontal cortex, which control rewarding behavior (41). The gray matter volume of the pre-frontal cortex develops into an inverted U-shape during adolescence (42, 43), and through this frontalization, one can develop the ability to control impulsiveness (44).

In this study, the ICU costs and 6-month total cost for young people were found to decrease, although there was no change in the total treatment costs for adults before and after the MECS implementation. Further, the number of days hospitalized for suicide attempters increased after the MECS implementation. This means that patients received sufficient treatment during the longer period of hospitalization at the same cost for adults and at a lower cost for adolescents after the MECS implementation. In our previous study on the speed and frequency of consultation using the MECS, the time required for a consultation reply after the MECS implementation was significantly reduced (Pre-MECS: 18.39 ± 14.41 h vs. Post-MECS: 11.53 ± 11.00 h), and the proportion of inpatient transfers to the Department of Psychiatry from other departments was significantly increased (Pre-MECS: 12.9% vs. Post-MECS: 36.4%) (45). Similarly, after the MECS implementation, prompt cooperation by the psychiatrist immediately after the physical condition of the patient in the ICU stabilized prevented unnecessary ICU stays, which reduced the ICU cost. Greater reduction in the hospital costs for young people may be because of a higher number of non-serious attempts in young people compared to those in adults. In other words, unnecessary ICU hospitalizations or treatments for suicide attempters reduced, which increased cost-effectiveness. This is consistent with previous studies that showed that psychiatric and general medical management can be provided at the same time for patients in need of psychiatric treatment, through the psychiatry-emergency unit during hospitalization, thereby improving cost efficiency (21, 22). Ensuring proper intervention based on a cooperative system, for patients with both physical and psychiatric problems that are difficult to treat in outpatient clinics, can also have a significant effect on reducing hospital costs (46).

Furthermore, when we compared costs by evaluating non-serious and serious suicide attempters in this study, we found a decrease in ICU costs for both non-serious and serious young people, and non-serious adult suicide attempters. However, in young people, ICU costs reduced whereas general ward costs increased for serious suicide attempters. This may be due to the quick cooperation of the multidisciplinary departments, which reduced unnecessary ICU treatments, especially in the non-serious groups. The internal medicine departments reduced the number of patients who were being hospitalized for unnecessarily long periods in the ICU due to the fear of suicide re-attempts (the ICU is considered safe against suicide re-attempt because of the possibility of quick intervention), or delayed consultation responses. The general ward costs appeared to have increased as patients in the ICU were quickly moved to the general ward for the rest of the necessary treatment. Another explanation for the increase in the general ward costs is that the patients were more likely to be transferred to the psychiatry department and receive long-term care. Meanwhile, evaluate cost-effectiveness, we analyzed inpatient expenses including expense for the ICU, a general hospital room, and total medical expenses over the next 6-months. Additionally, for evaluating hospital management or national policy, resource use after discharge of patients, such as extra-hospital emergency service use, absence from work due to illness, and mortality, can be included for measuring cost-effectiveness (47).

There are a few limitations of this study. First, it was conducted at a single institution. Since it was a tertiary hospital located in a large city, there may be selection errors due to regional restrictions and medical grades. Therefore, further research is needed at hospitals in different regions for longer periods of time to overcome these limitations. Second, this was a retrospective study, and there were limitations in obtaining information about various variables affecting suicide attempts, such as interpersonal relationships, economic status, and professional situations. Additionally, as this study is a retrospective study, for accurately grouping or defining suicide-related factors, such as planning and intentionality of suicide attempts is another limitation. These data were solely based on a previously collected questionnaire intended to be used by all hospitals that participated in the project, “Post-management Service for Suicide Attempters in the Emergency Room.” Further research is needed with a prospective design using a more intensive interview and standard questionnaires to overcome these limitations.

Fast and precise cooperation from the multidisciplinary departments for patients who attempted suicide by drug overdose reduced unnecessary ICU treatment and costs, especially in young attempters and those with a lower level of intentionality and lethality.

The data analyzed in this study is subject to the following licenses/restrictions: Due to the retrospective nature of this research, participants of this study did not agree for their data to be shared publicly; therefore, supporting data are not available. Requests to access these datasets should be directed to Sun Mi Kim, sunmikim706@gmail.com.

The studies involving human participants were reviewed and approved by The Institutional Review Board of Chung-Ang University Hospital. Written informed consent from the participants' legal guardian/next of kin was not required to participate in this study in accordance with the national legislation and the institutional requirements.

SMK and DHH were responsible for the conceptualization of this study and analyzed and interpreted the data. JHH, SIK, and MHS were responsible for data acquisition. SIK and SMK prepared the initial manuscript. DHH and JHO reviewed and edited the manuscript. All authors have critically reviewed and approved the final manuscript.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.