Characteristics of Japanese Teenage Suicide Attempters: A Retrospective Study Comparing Suicide Attempters with Young Adults

doi:10.21203/rs.3.rs-4927293/v1

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Characteristics of Japanese Teenage Suicide Attempters: A Retrospective Study Comparing Suicide Attempters with Young Adults

https://doi.org/10.21203/rs.3.rs-4927293/v1

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Background

Teenage suicide-related behaviors have been highlighted in Japan in recent years, but the background factors and characteristics of these behaviors have not been clarified. Therefore, we investigated the characteristics of teenage suicide attempters who were admitted to an emergency room.

Methods

The subjects were suicide attempters in their teens and twenties who were admitted to the Critical Care Medical Center of Nippon Medical School Hospital between January 1, 2010 and December 31, 2021. The means of suicide attempt, sociodemographic data, psychiatric diagnoses, and causes and motives of suicide attempts were retrospectively examined from medical records. Teenage suicide attempters were compared to those in their twenties for the acquired data, and logistic regression analysis was conducted to evaluate the influence on teenage suicide attempts of the aspects that have been shown to be closely associated with teenage suicides.

Results

Among the 860 suicide attempters between 2010 and 2021, 59 (6.9%) were teenage suicide attempters and 216 (25.1%) were suicide attempters in their twenties. The large number of females, history of self-harm, the great number of drug overdoses as a means of suicide attempts, and the large number of individuals with psychiatric disorders, especially with mood disorders and personality disorders, were commonly shared by suicide attempters in their teens and twenties. On the other hand, family problems, school problems and autism spectrum disorder significantly influenced teenage suicide attempters.

Conclusions

It was suggested that teenage suicide attempters may have attempted suicide due to environmental difficulties and conflicts about not being able to escape from them. It has become clear that teenage suicide attempters have unique characteristics and background factors, and that it is important to take these into account when taking measures to prevent teenage suicides.

Suicide attempters

youth

critical care medical center

autism spectrum disorder

social camouflaging

In recent years, teenage suicides have been highlighted in Japan. While the total number of suicides in Japan has been declining since 2010, the decline in the number of young suicides has been slow, and in particular, the number of teenage suicides has remained flat or even increased [1]. Therefore, teenage suicides are becoming relatively more prominent, although the number of teenage suicides is less than that of other age groups. Suicide is also the most common cause of death among teenagers in Japan, which is another reason why teenage suicides are getting a lot of attention [1]. Adachi et al. reported that 16.3% of Japanese elementary and junior high school students thought about death or self-harm for several days or more in the past week [2]. Nagamitsu et al. also reported that 25.7% of Japanese junior and senior high school students had suicidal ideation in the past year and 5.4% of them had suicide attempts in that period [3].

Although there is no clear explanation as to why the number of teenage suicides has not decreased in spite of the various measures to prevent suicides, it is assumed that teenage suicides have differing characteristics from those of other age groups. Several non-Japanese studies have reported on the characteristics of teenage suicides using psychological autopsy studies. Gould et al. compared 120 suicide victims under 20 years of age in New York City and its suburbs with 147 controls, reporting that school problems, family history of suicide attempts, poor communication between parents and children, and stressful life events were significant risks among suicide victims [4]. Other psychological autopsy studies have identified psychiatric problems such as previous suicide attempts, depression, and borderline personality disorder as risks for suicide in teenagers [5–8]. However, the social background of non-Japanese reports differs from that of Japan, so the findings on suicides presented in non-Japanese reports cannot be directly applied to the characteristics of suicides in Japan. No psychological autopsy studies have been conducted on teenagers in Japan.

Some studies have been conducted on severe suicide attempters in order to clarify the characteristics of teenage suicide. The history of previous suicide attempts has been reported as a major risk factor for teenage suicide in psychological autopsy studies, and it is believed that parts of the characteristics of teenage suicides may also be maintained in severe suicide attempters [5, 6]. Beautrais et al. studied 129 severe suicide attempters between 13 and 24 years old in New Zealand, reporting that problems with interpersonal relationships were the most common triggers [9]. In a study in Japan, Mikami et al. investigated 94 suicide attempters under 20 years of age and reported that males were less likely than females to receive psychiatric treatment and that more of them were diagnosed with an autistic spectrum disorder [10]. We have also previously reported a study of teenage severe suicide attempters admitted to an emergency room [11]. In that study, it was found that a greater proportion of severe suicide attempters under 18 years old were diagnosed with borderline personality disorder and had school problems, and that a smaller proportion had financial problems, compared to adults. However, all of the previous studies in Japan used the data from before 2010, and there have been no reports of studies in Japan on severe suicide attempters among teenagers in recent years.

While various suicide prevention measures have been implemented in Japan and have reduced the total number of suicides since 2010, the suicide rate among teenagers has not decreased, suggesting that the current suicide prevention measures in Japan are not sufficiently effective for teenagers. Therefore, clarification of the characteristics of current teenage suicide attempts in Japan in is an urgent issue. In order to clarify the characteristics of recent teenage suicide attempts empirically, the characteristics of teenage suicide attempters were investigated in the present study by comparing them with suicide attempters in their 20s, based on data from suicide attempters admitted to the Critical Care Medical Center (CCM) of Nippon Medical School Hospital. The social backgrounds of the individuals differed greatly according to age group, and these differences will strongly influence the characteristics of suicide attempters. Since analyzing multiple age groups together can make it difficult to determine the characteristics of suicide attempters, we chose a control group of suicide attempters in their 20s, whose characteristics are considered to be relatively close to teenage suicide attempters. The CCM of Nippon Medical School Hospital is located in the center of Tokyo, Japan, and admits 1,600-1,800 of the most physically demanding emergency patients each year.

Study design and sample

The subjects were suicide attempters in their teens and twenties admitted to the CCM of Nippon Medical School Hospital between January 1, 2010 and December 31, 2021. The assessment of suicide attempts was based on the definition provided by the Columbia Classification Algorithm of Suicide Assessment (C-CASA) [12]. In C-CASA, “suicide attempt” is defined as a potentially self-injurious behavior, and is associated with at least some intent to die as a result.

The means of suicide attempts, sociodemographic data, psychiatric diagnoses, and causes and motives of suicide attempts were retrospectively examined in the medical records of eligible suicide attempters. At the CCM of Nippon Medical School Hospital, psychiatrists examine almost all suicide attempters and evaluate their psychiatric diagnoses as well as the causes and motives of the attempts. Psychiatric diagnoses were made according to the Diagnostic

and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) or the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria [13, 14]. The causes and motives of suicide attempts were evaluated based on the classification of causes and motives of suicide used in the 2010 National Police Agency (NPA) statistics [15]. The classification items are listed in Table 1. However, in the NPA statistics, items related to mental disorders (“depression,” “schizophrenia,” “alcohol dependence,” “drug abuse,” and “other mental disorders”) are included in “health problems,” but since psychiatric diagnoses are evaluated separately in the present study, mental disorders were excluded from the causes and motives of suicide attempts. Although drinking alcohol prior to attempting suicide is known as a risk factor for suicide attempts [16], drinking alcohol prior to attempting suicide is not included as a classification item in the NPA statistics, and therefore, only drinking alcohol prior to attempting suicide was recalculated after being included in the “other” in the major category “other problems.” Psychiatric diagnoses and causes and motives for suicide attempts were evaluated by two or more experienced psychiatrists in agreement. When multiple means of suicide attempts, psychiatric diagnoses, and causes and motives of suicide attempts were identified, all of them were included. Psychiatric diagnoses and causes and motives for suicide attempts were evaluated by two or more experienced psychiatrists in agreement. When multiple means of suicide attempts, psychiatric diagnoses, and causes or motives for suicide attempts were identified, all of them were included.

Table 1

Items used for classification in the National Police Agency’s suicide statistics, 2010
Family problems
Parent-child relations, marital relations, relations with other family members, death in the family, pessimism over the family’s future, scolding from family members, worries about parenting, abuse, exhaustion by nursing or care, others
Health problems
Disease, depression, schizophrenia, alcohol dependence, drug abuse, other mental disorders, physical handicaps, others
Money problems
Bankruptcy, slump in business, redundancy, failure to find employment, poverty, debts (accumulated loans), debts (joint liability), debts (others), pressure for repayment from creditors, insurance paid by suicide, others
Work problems
Failure of the business, workplace relationship, unwanted transfer, work overload, others
Romantic problems
Marriage problem, broken heart, worries about adultery, trouble with boyfriend or girlfriend, others
School problems
Entrance examinations, career decisions, academic failure, relationship with teachers, bullying, relationship with schoolmates, others
Other problems
having his/her crime revealed, crime victim, suicide over someone’s death, loneliness, relationship with neighbors, others

Statistical analyses

Statistical analyses were conducted using SPSS Statistics 24. Chi-square test or Fisher's exact test was used to compare suicide attempters among teens and twenties in terms of sex, employment status, residential status, history of self-harm, history of psychiatric visits, means of suicide attempts, psychiatric diagnoses, and causes and motives of suicide attempts. As for employment status, in order to evaluate social participation commonly among teens and twenties, we categorized them into “unemployment or part-time employment” and “full-time employment or student.” To evaluate the influences on teenage suicide attempters of mood disorders, personality disorders, autism spectrum disorder, history of self-harm, family problems, and school problems, which have been reported to be closely associated with teenage suicides in previous studies, logistic regression analysis using the forced entry method was conducted and odds ratios (OR) and 95% confidence intervals (95%CI) were obtained. A significance level of p < 0.05 and two-sided probability were applied.

Between January 1, 2010 and December 31, 2021, 860 suicide attempters were admitted to the CCM of Nippon Medical School Hospital, of which 59 (6.9%) were in their teens and 216 (25.1%) were in their 20s. The results of the comparison of characteristics between suicide attempters in their teens and those in their 20s are shown in Table 2.

Table 2

Comparison of characteristics among suicide attempters in their teens and twenties.
	total (N = 275)	Ages 10–19 (N = 59)	Ages 20–29 (N = 216)	significance
Female/male	189/86 (68.7%/31.3%)	41/18 (69.5%/30.5%)	148 /68 (68.5%/31.5%)	NS^¶
Unemployment or part-time employment	133 (48.4%)	15 (25.4%)	118 (54.6%)	p < 0.001^¶	χ² = 15.828
Full-time employment or student	127 (46.2%)	43 (72.9%)	84 (38.9%)	p < 0.001^¶	χ² = 21.545
Living with family	130 (47.3%)	47 (79.7%)	83 (38.4%)	p < 0.001^¶	χ² = 31.613
Living alone	95 (34.5%)	7 (11.9%)	88 (40.7%)	p < 0.001^¶	χ² = 17.089
History of self-injury	170 (61.8%)	36(61.8%)	134 (62.0%)	NS^¶
History of psychiatric visits	204 (74.2%)	37 (62.7%)	167 (77.3%)	p < 0.023^¶	χ² = 5.160
Means of suicide attempts
Drug overdose	185 (67.3%)	35 (59.3%)	150 (69.4%)	NS^¶
Jumping from high place	49 (17.8%)	17 (28.8%)	32 (14.8%)	p = 0.020^¶	χ² = 6.202
Poisonous gas	19 (6.9%)	4(6.8%)	15 (6.9%)	NS^†
Other methods	30 (10.9%)	3 (5.1%)	27 (12.5%)	NS^¶
Psychiatric diagnosis
Substance-induced disorders	14 (5.1%)	0 (0%)	14 (6.5%)	p = 0.046^†
Schizophrenia and other psychotic disorders	33 (12.0%)	25 (11.6%)	8 (13.6%)	NS^¶
Mood disorders	65 (23.6%)	12 (20.3%)	53 (24.5%)	NS^¶
Anxiety disorders	19 (6.9%)	3 (5.1%)	16 (7.4%)	NS^†
Adjustment disorders	47 (17.1%)	6 (10.2%)	41 (19.0%)	NS^¶
Personality disorders	59 (21.5%)	10 (16.9%)	49 (22.7%)	NS^¶
Intellectual disability	13 (4.7%)	3 (5.1%)	10 (4.6%)	NS^†
Autism spectrum disorder	27 (9.8%)	17 (28.8%)	10 (4.6%)	p < 0.001^¶	χ² = 30.611
Attention-deficit/hyperactivity disorder	9 (3.3%)	3 (5.1%)	6 (2.8%)	NS^†
Other psychiatric disorders	1 (0.4%)	0 (0.0%)	1 (0.5%)	NS^†
None	12 (4.4%)	4 (6.8%)	8 (3.7%)	NS^†
Causes and motives for suicide attempts
Family problems	59 (21.5%)	23 (39.0%)	36 (16.7%)	p < 0.001^¶	χ² = 13.696
Parent-child relations	37 (13.5%)	18 (30.5%)	19 (8.8%)	p < 0.001^¶	χ² = 18.761
Health problems	9 (3.3%)	0 (0.0%)	9 (4.2%)	NS^†
Financial problems	26 (9.5%)	0 (0.0%)	26 (12.0%)	p = 0.005^¶	χ² = 7.843
Work problems	47 (17.1%)	2 (3.4%)	45 (20.8%)	p < 0.001^¶	χ² = 9.951
Romantic problems	73 (26.5%)	3 (5.1%)	70 (32.4%)	p < 0.001^¶	χ² = 17.742
Trouble with boyfriend or girlfriend	43 (15.6%)	1 (1.7%)	42 (19.4%)	p < 0.001^¶	χ² = 11.068
School problems	34 (12.4%)	24 (40.7%)	10 (4.6%)	p < 0.001^¶	χ² = 55.579
Career decision	6 (2.2%)	4 (6.8%)	2 (0.9%)	p = 0.021^†
Academic failure	12 (4,4%)	7 (11.9%)	5 (2.3%)	p = 0.005^†
Relationship with schoolmates	2 (0.7%)	2 (3.4%)	0 (0%)	p = 0.045^†
Others	13 (4.7%)	10 (16.9%)	3 (1.4%)	p < 0.001^†
Other problems	81 (29.5%)	11(18.6%)	70 (32.4%)	p = 0.040^¶	χ² = 4.225
Having his/her crime revealed	2 (0.7%)	2 (3.4%)	0 (0%)	p = 0.045^†
Others	69 (25.1%)	8 (13.6%)	61 (28.2%)	p = 0.021^¶	χ² = 5.314
Drinking alcohol prior to attempting suicide	36 (13.1%)	2 (3.4%)	36 (13.1%)	p = 0.013^¶	χ² = 6.213
^¶chi-square test, ^†Fisher's exact test

The sex ratio was 41 (69.5%) females and 18 (30.5%) males in their teens, compared to 148 (68.5%) females and 68 (31.5%) males in their 20s, with no significant difference between the two groups. Regarding employment status, the percentage of unemployment or part-time employment was significantly greater among those in their 20s (chi-square test, χ² = 15.828, p < 0.001). In contrast, the percentage of full-time employment or students was significantly larger among those in their teens (chi-square test, χ² = 21.545, p < 0.001). Regarding living conditions, the percentage of those living with family was significantly greater among teenagers (chi-square test, χ² = 31.613, p < 0.001). Meanwhile, the percentage of those living alone was significantly larger among those in their 20s (chi-square test, χ² = 17.089, p < 0.001). A history of self-injury was high in both groups, 36 of 59 (61.8%) among teenagers and 134 of 216 (62.0%) among those in their 20s, but with no significant differences between the two groups. The percentage of those with a history of psychiatric visits was significantly greater among those in their 20s (chi-square test, χ² = 5.160, p = 0.023). The most common means of suicide attempts for both groups were drug overdose, jumping from high place, and poisonous gas, in that order, but the percentage of jumping from high place was significantly higher among teenagers (chi-square test, χ² = 6.202, p = 0.020).

Those with some kind of psychiatric diagnosis were 55 of 59 (93.2%) of those in their teens and 208 of 216 (96.3%) of those in their 20s, indicating that the majority of both groups had some kind of psychiatric diagnosis. The percentages of those diagnosed with mood disorders and personality disorders were large for both teens and twenties. In addition, the percentage of those diagnosed with autism spectrum disorder was significantly higher for teenagers (chi-square test, χ² = 30.611, p < 0.001). The percentage of those diagnosed with substance-induced disorders was not found among teenagers, but was significantly high among those in their 20s (Fisher’s exact test, p = 0.046).

There were clear differences in tendencies regarding the causes and motives of suicide attempts between teenagers and those in their 20s. Among teenagers, school problems, family problems, and other problems were the most common causes and motives of suicide attempt, in that order, while among those in their 20s, romantic problems and other problems were the most common causes and motives of suicide attempt in equal numbers, followed by work problems. For family problems (chi-square test, χ² = 13.696, p < 0.001) and school problems (chi-square test, χ² = 55.579, p < 0.001), the percentages of applicable persons were significantly higher among teenagers. On the other hand, the percentages of applicable persons were significantly higher for financial problems (chi-square test, χ² = 7.843, p = 0.005), work problems (chi-square test, χ² = 9.551, p < 0.001), romantic problems (chi-square test, χ² = 17.742, p < 0.001), and other problems (chi-square test, χ² = 4.225, p = 0.040) among those in their 20s. In the subcategories, the percentages of applicable persons in their teens were significantly higher for parent-child relationship (chi-square test, χ² = 18.761, p < 0.001) in family problems, career decision (Fisher's exact test, p = 0.021) in school problems, academic failure (Fisher's exact test, p = 0.021) in school problems, relationship with schoolmates (Fisher's exact test, p = 0.045) in school problems, others (Fisher's exact test, p < 0.001) in school problems, and having his/her crime revealed (Fisher's exact test, p = 0.045) in other problems. On the other hand, the percentages of applicable persons in their 20s were significantly higher for trouble with boyfriend or girlfriend (chi-square test, χ² = 18.761, p < 0.001) in romantic problems and others (chi-square test, χ² = 5.314, p = 0.021) in other problems. The percentage of applicable persons in their 20s was also significantly higher for drinking alcohol prior to attempting suicide, which is classified as others in other problems (chi-square test, χ² = 6.213, p = 0.013).

The results of logistic regression analysis are shown in Table 3. Autism spectrum disorder (OR: 7.297, 95%CI: 2.541–20.956), family problems (OR: 2.860, 95%CI: 1.355–6.038), and school problems (OR: 14.338, 95%CI: 5.557–36.998) had significant influences on teenage suicide attempts.

Table 3

Risk factors for suicide attempts by teenagers compared to those in their 20s
	odds ratio	95% confidence interval
Mood disorders	1.289	0.518–3.207	p = 0.586
Personality disorders	1.752	0.679–4.520	p = 0.246
Autism spectrum disorder	7.297	2.541–20.956	p < 0.001
History of self-injury	1.145	0.532–2.465	p = 0.728
Family problems	2.860	1.355–6.038	p < 0.001
School problems	14.338	5.557–36.998	p < 0.001

In order to identify the characteristics of teenage suicide attempters, we used those in their 20s as a comparison group, the characteristics of which are considered to be relatively closer to those of teenagers than to other age groups. The results of this study revealed many similarities between suicide attempters in their teens and twenties, but there were also some distinct differences between the two groups. Characteristics commonly observed among teens and those in their twenties in this study included a greater number of females, a greater number of those with a history of self-injury, a greater number of suicide attempts due to drug overdoses, and a greater number of those with psychiatric disorders, especially mood disorders and personality disorders. These results are generally consistent with previous studies conducted on young suicide attempters [10, 11, 17].

One of the characteristics of teenage suicide attempters observed in this study was strong influences from their families. Compared to suicide attempters in their 20s, fewer suicide attempters in their teens lived alone, with more living with their families. In addition, compared to suicide attempters in their 20s, suicide attempters in their teens included a smaller percentage of those with financial problems, while suicide attempters in their teens had a larger percentage of those with family problems, especially parent-child relations. Logistic regression analysis also showed that family problems had a significant influence on teenage suicide attempters. The NPA's data on suicides in Japan also shows a large percentage of teenagers with family problems, especially parent-child relations, as a cause and motive of suicide [18]. In a psychological autopsy study by Lee et al. in South Korea, an Asian country, conflict with mother was also identified as a recent trigger in teenage suicides [8]. Although non-suicidal self-harm, Ma et al. reported maternal over-interference as a risk factor in a survey of middle school students in China, also an Asian country [19]. The parent-child relationship is also thought to be an important risk factor for teenage suicide attempters in Japan.

In this study, suicide attempters in their teens were more likely to be full-time employees or students and less likely to be unemployed or part-time employees than those in their 20s. In addition, school problems were the most common causes or motives for suicide attempts among teenagers, whereas romantic problems were the most common causes or motives for suicide attempts among those in their 20s, rather than school problems or work problems. These results suggest that suicide attempters in their teens may be more likely than those in their 20s to attempt suicide due to problems and worries in their social situations. In other words, for suicide attempters in their teens, the difficulty of remaining in social situations is a major factor in their suicide attempts.

The difficulty of remaining in social situations may also be related to the prominence of teenage suicide attempters with autism spectrum disorder in this study. In recent years, reports of suicide-related behaviors in persons with autism spectrum disorder have increased. Although most of the reports dealt with adult cases, a high suicide risk has been noted for persons with autism spectrum disorder [20–22]. Regarding youths with autism spectrum disorder, a meta-analysis by O'Halloran et al. reported that 25.2% had suicidal ideation, 8.3% made suicide attempts, and 0.2% died by suicide [23]. It has been pointed out that suicide-related behaviors in persons with autism spectrum disorder have been associated with “social camouflaging,” the attempt to hide the characteristics of autism spectrum disorder in order to conform to social situations. Although reported in adult cases, Cassidy et al. reported that “social camouflaging” was a predictor of suicide risk as well as non-suicidal self-injury in persons with autism spectrum disorder [24]. While there are no reports yet on “social camouflaging” and suicide-related behaviors in children and adolescents with autism spectrum disorders, Ross et al. reported that “social camouflaging” was also a predictor of anxiety and depression in children and adolescents with autism spectrum disorder [25].

In consideration of these findings, the reason why suicide attempters with autism spectrum disorder in their teens were more conspicuous than those in their 20s in this study may be that the difficulty of remaining in social situations due to “social camouflaging” was strongly reflected in suicide attempters with autism spectrum disorder in their teens.

A significantly higher percentage of jumping from high place was observed among teenagers as the means of suicide attempts. It has been previously reported that suicide by jumping from high place is a conspicuous finding in teenage suicides, and especially in Asian countries [26, 27]. Park et al. commented on the high prevalence of jumping from high places as a means of suicide attempts among teenagers, noting the high impulsivity and the possibility of copycat suicides [27]. However, while suicide attempts by jumping from high places were more common among teens in this study, drug overdose was actually the most common means of suicide attempts, suggesting that drug overdose is a more serious problem for suicide attempts among teenagers in Japan.

Limitations

There are several limitations to this study. The first is that this study was conducted at a single medical facility. Therefore, the sample size is relatively small, and some categories have only a small number of applicable items. Results for such categories should be carefully construed. In addition, although Nippon Medical School Hospital is located in central Tokyo, there are regional differences in the characteristics of suicide attempts, so the characteristics of suicide attempts observed in this study may not match those of the whole of Japan. We believe that the results of this study also need to be construed in this regard. Nevertheless, there are many young people moving into Tokyo from other prefectures, and we believe that Tokyo is an appropriate place to conduct a survey on suicide attempts among young people.

The second limitation is that this was a retrospective study based on medical records and did not use objective methods such as structured interviews in investigating psychiatric diagnoses and the causes and motives of suicide attempts. However, to compensate for those shortcomings, we used a consensus from at least two psychiatrists to assess the psychiatric diagnosis and the causes and motives of suicide attempts.

The results of this study suggest that, in contrast to adults who can choose their own environment to some extent, teenagers are unable to escape from difficulties in their given environment, such as home and school, and that their conflicts may lead them to making suicide attempts. The results of this study indicate that teenagers have different background factors that lead to suicide attempts compared to adults, and it is important to take these factors into account when taking measures to prevent teenage suicide.

CCM

critical care medical center

C-CASA

Columbia Classification Algorithm of Suicide Assessment

DSM-IV-TR

Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision

DSM-5

Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition NPA:National Police Agency

odds ratios

95%CI

95% confidence intervals

Ethics approval and consent to participate

This study has been approved by the Ethics Committee of Nippon Medical School Hospital (B-2020-113). In addition, this study was conducted in accordance with the provisions of the Declaration of Helsinki. Informed consent was not obtained because only anonymized information was used for data collection. The Ethics Committee of Nippon Medical School Hospital waived the need for informed consent due to this being a retrospective study. It was clarified in the opt-out section of the website that the subjects of the study were informed about the purposes, methods and publication of the results, and were guaranteed the opportunity to refuse participation.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Funding

Not applicable.

Author Contribution

All authors contributed to the conception and design of the study. RN and YO contributed to the data collection and performed the statistical analyses. RN wrote the first and final drafts with review and comments from all authors listed. All authors read and approved the final manuscript.

Acknowledgements

We thank Dr. Yoshitaka Kawashima and Dr. Ken Yamamoto for their collaboration with the data collection.

Availability of data and materials

The datasets generated and/or analysed during the current study are not publicly available due to the used data protection declaration, but are available from the corresponding author upon reasonable request.

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No competing interests reported.

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Characteristics of Japanese Teenage Suicide Attempters: A Retrospective Study Comparing Suicide Attempters with Young Adults

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