In Korea, several types of chemical disinfectants that had been widely used in humidifiers since 1994 were found to be associated with lung injury, including interstitial pneumonitis and widespread lung fibrosis,12 collectively referred to as humidifier disinfectant-associated lung injury (HDLI). In 2011, the Korea Centers for Disease Control and Prevention and the Korean Ministry of Environment began a program to collect information on individuals with respiratory disease, including lung injury, who presumed their disease to be related to the use of humidifier disinfectants (HDs), in order to determine the veracity of these claims. Approximately 75.6% of Korean children used humidifiers, and 31.1% of children were exposed to HDs.3 As of March 2018, the number of cases of respiratory damage reported by people who thought their diseases were related to HDs exceeded 6,000. Among these cases, to date, a total of 416 people (179 deaths and 237 survivors) have been judged as having suffered from HDLI.4
Though there have been various studies on related issues such as the examination of causal relationships between respiratory damage and HD use,156789 discussion on a national surveillance system to track toxic chemical substances,10 and the government's legal liability,11 few studies focusing on psychological responses among victims have been conducted. Considering that several studies related to the sequelae of toxic chemical substance disasters pointed out physical and psychological symptoms such as posttraumatic stress disorder (PTSD), anxiety, and depression among victims,121314 it is important to investigate psychological responses in the aftermath of HD disasters.
The study and consent exemptions were authorized by the Institutional Review Board (IRB) of the NCMH (IRB No. 116271-2016-03).
Among 26 victims (10 men, 38.5%; mean age, 46.2 years; standard deviation [SD], 11.2), 11 (42.3%) had reported the exposure period to HD substances, which was a minimum of 3 months to a maximum of 120 months (median 6 months). Forty-seven family members of victims (21 men, 44.7%; mean age, 42.7 years; SD, 7.6) included 32 (68.1%) parents and 13 (27.7%) spouses. Forty-five bereaved family members (25 men, 55.6%; mean age, 42.8 years; SD, 7.0) included 28 (70.0%) parents and 11 (27.5%) spouses of the deceased.
The frequency of psychological responses among victims and family members including the bereaved is described in Table 1. It was revealed that 65.4% of victims had respiratory symptoms. Anxiety/fear and depression were the most frequently observed psychological symptoms in victims, significantly higher than in the bereaved group (38.5% and 6.7%, P = 0.001; 35.5% and 8.9%, P = 0.003, respectively). Also, the level of anger felt by victims (30.8%) was significantly higher than other groups (2.1% and 6.7%, P < 0.001).
With respect to the clinical severity of psychological distress demonstrated by the CGI-S, only 7.7% of victims were classified into the “normal” group, whereas scores of 34.6% of victims were 4–5 (“slightly bad” group, possible medical treatment). Moreover, 1.2% of victims scored higher than 6 (“very bad” group, possible hospitalization). Additionally, during the interviews, victims expressed distrust and anxiety regarding chemical substances and concerns about the respiratory aftereffects of HD use, as well as chronic depression including helplessness and decline of self-confidence.
Anxiety/fear and depression were the most common symptoms among family members of victims (19.1% and 21.3%, respectively). Although family members of victims had not suffered damage to the respiratory system, they, along with the bereaved, had also experienced respiratory symptoms (21.3% and 11.1%).
However, the bereaved showed a relatively higher rate of alcohol/smoking abuse and insomnia than other psychological responses.
The findings from this study demonstrated that HD disaster victims and their family members including the bereaved still experienced psychological distress even 7 years after the event. However, the characteristics of psychological symptoms among subject groups were slightly different; victims frequently showed anxiety and fear, whereas the bereaved showed alcohol/smoking abuse and insomnia, which indicates chronic psychological distress.
With regard to the severity of psychological distress using the CGI-S, 34.6% of victims were classified into the “slightly bad” group that needed to consider psychiatric treatment. In several studies, the prevalence of PTSD in the first year after human-made/technological disasters has been documented to range between approximately 25 and 75 percent, which is generally higher than that documented in studies after natural disasters.16 Especially in terms of the aftermath of toxic chemical substance disasters, it has been reported that prolonged psychological symptoms such as anxiety last regardless of the elapse of time. For example, among the 474 people who were exposed to methyl isocyanate gas in India, the frequency of anxiety was 65% and depression 25% even 9 years after the disaster.13 Similarly, 32% of the Tokyo subway disaster victims exposed to sarin gas experienced PTSD symptoms even after 5 years.12 The reasons for psychological responses lasting for such long periods after disasters could include hidden exposure and prolonged potential complications including cancer and genetic disorders.1718
Compared to the grief and anger of family members of those who succumbed to Middle East Respiratory Syndrome and received similar psychological support from the NCMH in 2015 (81.3% and 51.6%, respectively), the grief and anger of bereaved family members of HD victims were lower. This implies that the psychological responses of the bereaved might be relieved by mourning victims' deaths. The relatively high rates of alcohol/smoking abuse and insomnia among bereaved family members of HD disaster victims imply that the bereaved might be suffering from chronic psychological distress.
It was revealed that family members of victims experienced not only anxiety and fear but also respiratory symptoms, even though their respiratory systems might not have been damaged. This result would be understandable considering previous findings, as follows: 1) toxic chemical substance disasters trigger high anxiety because it can be difficult to identify prolonged complications18 and 2) somatization symptoms observed in toxic chemical substance disaster victims need to be regarded from both the organic and psychogenic perspectives because physical symptoms can be related to psychiatric symptoms such as anxiety, depression, and anger as well as the degree of exposure to toxic chemical substances.17
Prolonged psychological distress among victims and their family members (including the bereaved) might be caused by the absence of adequate psychological support such as psychological first aid immediately after the event. According to Ponsford et al.,19 patients in the non-intervention group reported more symptoms and were significantly more stressed than those in the early intervention group, which implies that psychological intervention immediately after a traumatic event mitigates psychological distress. Also, Brewin et al.20 reported that outreach with screening, linked to the provision of evidence-based treatment, significantly mitigated posttraumatic symptoms among London bombing victims. In addition to the absence of psychological support, there can be several stressors such as monetary compensation and legal suits that arouse prolonged psychological distress. In fact, there is an outpouring of blame and anger from victims and their families toward the administration in terms of neglecting their duties in managing HD products as well as manufacturers and sellers.
Limitations of this study may be derived from analyzing the initial counseling records via telephone, which might hinder detailed examination of mental health of HDs victims. However, considering that psychological aftereffects of HD disaster have been disregarded due to the legal problems related to judgement and compensation, it is valuable to reveal the need of psychological intervention as well as financial compensation for the HDs victims. Further research is needed to elucidate the predictors of psychological responses and which way of intervention will be as effective when toxic chemical disasters occur.
In conclusion, the findings from this study imply that the psychological aftereffects of HD disasters continue despite the time elapsed. Also, victims of HD disasters mainly experience anxiety/fear, depression, and anger while bereaved family members show relatively high rates of alcohol/smoking abuse and insomnia. Hence, it is important to provide psychological support to victims and their families, focusing on the characteristic symptoms of each group as well as monetary compensation for the damage caused.