Effects of age on suicide attempts by medication in patients transferred to the emergency rooms of two advanced medical centers: A retrospective chart review of the DJ project

Abstract Aims The means of suicide vary, but in cases of impaired consciousness, it is often difficult to determine the initial treatment because it is not known whether a patient has overdosed or used pesticides or poisons. Therefore, we investigated the clinical characteristics of suicide by medication in patients with suicide attempts who were brought to the emergency department, especially the influence of age. Methods Patients with suicide attempts were transported to the two hospitals. There were 96 males (38.4%) and 154 females (61.6%). The mean age was 43.5 ± 20 years, and both males and females were most often in their 20s. Data on sex, age, motive for suicide, means of suicide attempt, psychiatric diagnosis, length of hospital stay, and place of discharge were retrospectively analyzed. Results The average age of the patients by means of suicide attempt was 40.5 years for “prescription drugs,” 30.2 years for “over‐the‐counter drugs,” and 63.5 years for “pesticide/poison.” For each means of suicide attempt, there was a significant difference in age among patients with suicide attempts using “prescription drugs,” “over‐the‐counter drugs” and “pesticides/poisons.” There was a statistical bias in the means and reasons for each suicide attempt. Conclusion The results showed that the age of patients who used over‐the‐counter medicines and pesticides and poisons varied significantly. It was thought that pesticide use should be considered first, especially when patients aged 50 years and over are brought to the hospital with impaired consciousness due to suicide attempts.


| INTRODUC TI ON
In 2019, a total of 759 028 (523 883 males and 235 145 females) deaths due to suicide were reported worldwide. 1 Moreover, rates of suicidal behavior among youth have gradually increased over the past 15 years and continued to rise during the COVID-19 pandemic.
This trend places a burden on mental health services and calls for important developments in the detection of risk and the provision of interventions to reduce risk. 2 A history of suicide attempts is known to be an important and the most powerful risk factor for suicide. 3,4 In particular, when a patient with past suicide attempts is brought to the hospital for any kind of suicide attempt, prompt identification of the means of suicide is important to save their life. In psychiatric care, there are many opportunities to encounter patients with psychiatric disorders who have suicidal ideation and self-harm. Especially in general hospitals with emergency medical services, there are many cases in which patients who have attempted suicide are transported to the hospital and require careful treatment for both physical and mental health issues. In some cases, the details of the patient's circumstances at the time of the suicide attempt are known from family members or acquaintances who were nearby, while in other cases, the patient is found unconscious, and it is unclear what the means of the suicide attempt was. There are various means of suicide, but in the case of impaired consciousness, it is often difficult to determine the initial treatment because it is often not known whether a patient has overdosed ("OD") or used pesticides/poisonous substances. If the characteristics of the drug can be clarified to some extent based on clinical notes, it will provide important information for initial lifesaving treatment.
Therefore, we investigated the clinical characteristics of suicide attempts by medication in patients brought to the emergency room. The mean age was 43.5 ± 20 years, and both males and females were most often in their 20s. The most common psychiatric diagnosis was mood disorders (F3) (34.1%). We determined what the patients had taken based on medicine shells provided by family members and from family members' testimonies. Data on sex, age, motive for suicide, means of suicide attempt, psychiatric diagnosis, length of hospital stay, and place of discharge were retrospectively analyzed. In addition, clinical characteristics were compared according to the three suicide attempt methods: prescription drugs, over-the-counter drugs, and pesticides/poisons. The ANOVA and chi-square tests were used for statistical analysis, and p < 0.05 was considered significant. Multiple comparisons were performed using Tukey's test.

This study was approved by the Clinical Research Review
Committees of Dokkyo Medical University Hospital, and consent was obtained from the subjects by opt-out.

| DISCUSS ION
In this study, for each means of suicide attempt by medication, there was a significant difference in the age of the patients who had taken "prescription drugs," "over-the-counter drugs," and "pesticides/poisons." Among these, over-the-counter drugs were more common among young adults, while prescription drugs tended to be used by young adults and adolescents and pesticides tended to be used by older adults. This suggests that over-thecounter drugs are easily accessible in Japan and that doctors may prescribe them easily.
The percentage of ODs (including prescription, over-the-counter, and other ODs) among patients with suicide attempts in this study was 57.3%, an extremely high percentage compared to previous studies. A previous study found that in 2000, approximately onequarter of suicide attempts in the U.K. 5 In addition, according to the Centers for Disease Control and Prevention (CDC), approximately 15% of suicide attempts in the United States in 2016 were caused by ODs, and the percentage of suicide attempts by using opioids increased from 2.2% in 1999 to 4.3% in 2014%. 6 A higher percentage of females than males was also found to have used prescription and over-the-counter medication (69.9% and 66.7%, respectively), while males were slightly more likely to have used pesticides/poisonous substances (54.5%). This seems to be similar to previous reports in which men choose relatively more lethal methods of suicide attempts compared to women. 7,8 It has long been recognized that the characteristics of suicidality in children and adolescents differ from those in adults, and differences in the means of suicide attempts across age groups may provide useful criteria for the evaluation and treatment of unconscious patients with suicide attempts.
In addition, the tendency to use relatively lethal means of suicide, such as pesticides and burning, was more pronounced in the older age groups, consistent with the report by Hawton et al. reporting that suicide rates per population are generally higher in older age groups than in younger age groups and that the proportion of deaths (attempts) is also higher. [8][9][10] This study had some limitations. There were several cases in which more than one means was used at the same time. In such cases, we counted them both and performed the statistics. In addition, the findings may not be applicable outside Japan because domestic circumstances may be involved, or the cultural backgrounds may be different.
In conclusion, the results of this study showed that overdose and pesticide/toxin use were characterized by age and sex. It is thought that pesticide use should be considered first thing, especially when patients aged 50 years and over are brought to the hospital with impaired consciousness due to suicide attempts. F I G U R E 1 Histogram of the age distribution. Gray indicates females, and black indicates males. The top diagram (A) shows the age distribution of suicide attempts with prescription drugs, the middle diagram (B) shows the age distribution of suicide attempts with over-the-counter drugs, and the bottom diagram (C) shows the age distribution of suicide attempts with pesticides and poisons.