Suicide in adolescents is a worldwide issue, and there is an obvious need to predict risk factors for suicidal ideation or attempt . Previous suicide attempts can be used as important predictive factors of recurrence, while additional studies are needed to predict subsequent harmful attempts which affect the maintenance of adolescents’ normal lives.
This study aimed to evaluate whether differences in suicide methods and changing suicide methods in multiple attempts can be used as predictive factors of later serious suicide attempts. Four main methods were identified in this study: falling and hanging (both classified as fatal methods), and DI and self-harm with suicidal ideation (both classified as non-fatal methods) .
Unlike previous studies, the current study found that recurrent suicide attempts did not increase the success rate [8, 9] and that changing methods and the number of methods used did not have a significant relationship with meaningful outcome. This may be because many previous studies [6–10, 13–17] focused on the recurrence rate of suicide attempts, and not the severity of each attempt. However, unlike adults, young adults tend to be impulsive when choosing to attempt suicide and do not prepare their methods, or they tend to choose available or easily accessible non-fatal methods that are less severe [6, 10]. Thus, using adolescents’ histories of previous suicide attempts as predictive factors of severity provides a weaker correlation than using the same for adults.
In this study, no clear relationship between sex, age, psychiatric history, or number of suicide attempts and successful suicide attempts was evident. However, methods of suicide attempts were statistically significant with outcomes. Patients who chose DI as a method achieved successful suicide (P value <0.001), while patients who selected self-harm achieved successful suicide 0.38 times less than DI (P value 0.025). This result contradicts that of previous studies  and differs from previous works in its definition of meaningful attempts, i.e., when an individual expires. However, we define lethality of suicide attempts more broadly so that we can focus on providing specific care for patients before they actually achieve suicide
It is obvious that fatal methods have more lethality than non-fatal methods . According to this study’s research, patients who successfully attempted suicide eventually selected DI instead of self-harm among non-fatal methods. Moreover, patients who selected DI as an index method or present method had a significantly higher success rate than patients who chose self-harm. Historically, DI has been a more fatal method than self-harm among non-fatal methods. Therefore, both the number of previous suicide attempts and a change in method to DI must be considered as important factors by clinicians when making decisions regarding emergency hospitalization in pED (although they are not absolute predictive factors).
This study has a few limitations. First, previous psychiatric histories can vary when records are based solely on patients’ memories. Therefore, some data may have been missed and confounding factors, such as family composition, may not have been included. Second, there was a single center bias where there was a tendency to admit patients more readily when they had previously visited psychiatric outpatient clinics, regardless of severity. Third, prospective cases with long term output, including post-accident care, should be included in future studies. It was difficult to determine methods of subsequent suicide attempts after pED visits because later contact was lost due to the retrospective study design. Of the 69 (30.4%) patients connected with the social care service team (of 227 patients total), only 21(30.4%) agreed to follow ups, and only 11 completed case management a total of four times or re-connected to other social care service teams, while others refused or could not participate in post-accident care. Several studies have reported that the mortality and recurrence rate of suicide significantly decreased in patients who underwent follow-up care compared with those who did not [17, 20]. Thus, because the prospective study design does not include long term output, mortality would increase. Fourth, the term DI should be clarified in more detail. In this study, all types and amounts of drugs were regarded as potentially lethal. However, previous studies distinguished between different types of drugs and found that specific drugs carried higher risks. Additionally, young adults tend to acquire over-the-counter drugs because many other drugs are not easily acquired . Thus, future studies should consider kinds and amounts of drugs based upon adolescents’ characteristics. Finally, social issues should be considered. In this study, the success rate of suicide was especially evident among the 17 YO age group, a time when adolescents can experience extensive stress in high school. Several studies also mentioned the specific circumstances of adolescents  and how hypercompetitive educational circumstances can lead to an exponential increase in suicide [11, 12]. Future studies should consider social circumstances when examining suicide methods and success rates.