Traffic Injury Prevention
ISSN: 1538-9588 (Print) 1538-957X (Online) Journal homepage: http://www.tandfonline.com/loi/gcpi20
Road Traffic Suicide in Switzerland Saskia Gauthier, Thomas Reisch, Vladeta Ajdacic-Gross & Christine Bartsch To cite this article: Saskia Gauthier, Thomas Reisch, Vladeta Ajdacic-Gross & Christine Bartsch (2015) Road Traffic Suicide in Switzerland, Traffic Injury Prevention, 16:8, 768-772, DOI: 10.1080/15389588.2015.1021419 To link to this article: http://dx.doi.org/10.1080/15389588.2015.1021419
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Traffic Injury Prevention (2015) 16, 768–772 C Taylor & Francis Group, LLC Copyright ISSN: 1538-9588 print / 1538-957X online DOI: 10.1080/15389588.2015.1021419
Road Traffic Suicide in Switzerland SASKIA GAUTHIER1, THOMAS REISCH2,3, VLADETA AJDACIC-GROSS4, and CHRISTINE BARTSCH1 1
Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland Hospital for Psychiatry, M¨unsingen, Switzerland 3 University Hospital of Psychiatry Bern, Bern, Switzerland 4 University Hospital of Psychiatry, University of Zurich, Switzerland
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2
Received 4 December 2014, Accepted 17 February 2015
Objective: To determine details of road traffic suicides in Switzerland between 2000 and 2010 and to look at our results in relation to studies from other countries. Methods: Retrospective data analysis of road traffic suicides extracted from the database of all suicides investigated by Swiss institutes of forensic medicine between 2000 and 2010 using a standardized assessment sheet. Results: Out of 4,885 suicides in Switzerland, we identified 76 cases (1.56%) of road traffic suicide. Twenty-three cases had to be excluded because, although the forensic medical experts suspected suicide, they could not establish it for sure. That left 53 cases (1.02% of all suicides), mostly unmarried men, who were on average 9 years younger than the study population as a whole. Most collided with other vehicles, mainly other cars, and usually on main highways or country roads. In most cases, the cause of death was multiple injuries. Other persons were killed 4 times more often than with other suicide methods. Toxicology screening was performed significantly more frequently than with other methods but more often proved negative. Acute psychiatric problems were commonly assumed to be the underlying reasons. Suicide notes were left by only 20%, a lower proportion than in the study population as a whole. Conclusions: Road traffic suicides account for approximately 1% of all suicide methods used in Switzerland, although unclassifiable cases indicate that the rate might be higher. Every road traffic crash should therefore be routinely investigated by an interdisciplinary team and suicide should be considered as the possible cause. Keywords: motor vehicle, self-harm, driver suicide, collision, Swiss, forensic, SNSF
Introduction Road traffic injuries and fatalities due to road traffic crashes are a major public health problem worldwide (World Health Organization [WHO] 2004). According to the WHO, approximately 127,000 people die in road traffic accidents each year in Europe (Raciopii et al. 2004). In Switzerland, 269 people died and 21,379 people were injured in this way in 2013 (Federal Statistics Office [FSO] 2014). The Swiss road safety program “Via Secura,” which started in 2013, aims to reduce road traffic fatalities significantly. Its main aspects are awareness of social problems, the behavior of road users, and the safety of motor vehicles and the infrastructure (Federal Roads Office 2014). Suicide in road traffic is not part of Via Secura, although international studies have found evidence that road traffic suicides are underestimated because they are often misinterpreted as accidents (Murray and de Leo 2007; Ohberg
Managing Editor David Viano oversaw the review of this article. Address correspondence to Saskia Gauthier, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190 8057, Zurich, Switzerland. E-mail: [email protected]
et al. 1997; Routley et al. 2003). It is assumed that 1–7% of all road traffic fatalities are really suicides (Routley et al. 2003). In Switzerland, 1,037 people died by suicide in 2012, making this the leading cause of nonnatural deaths. Hanging, shooting, and intoxication were the most commonly used methods (FSO 2014), but official statistics provide no data on suicide in traffic. The present study is part of a large-scale research project founded by the Swiss National Science Foundation (SNSF). The overall aim is to obtain more detailed knowledge about suicide methods than is provided by the FSO, with the objective of developing new prevention strategies based on the newly acquired information. From the data pool of 4,885 suicides (SNSF 2013), we extracted road traffic suicides, including collisions and pedestrian suicides, with the following aims: 1. To determine details of suicide in traffic in Switzerland and to look at our results in relation to studies from other countries. 2. To compare selected aspects of road traffic suicide with data from the other suicide methods in Switzerland, in order to determine any possible differences.
Road Traffic Suicide in Switzerland
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Methods The present study consisted of a retrospective data analysis of suicides in road traffic investigated forensically, using a standardized assessment sheet. The data collection methods were identical to those described by the authors in “Self-Burning, a Rare Suicide Method in Switzerland and Other Industrialized Nations—A Review” (Gauthier et al. 2014), with the exception that the cases extracted were road traffic suicides. This study is also part of the SNSF project Suicide in Switzerland: A Detailed National Survey of the Years 2000 to 2010, which retrospectively examined all cases of completed suicide that had been investigated, with a full autopsy or simple external examination, by institutes of legal and forensic medicine in Switzerland. The databases of all of these institutes were searched for suicides occurring in the period 2000–2010 and 4,885 cases were included. In Switzerland, forensic medical examiners define the manner of death after having performed their examinations (external examination and/or autopsy and additional analysis, such as toxicological) usually in combination with results of police investigation. Only those cases where suicide was the definite manner of death were included. Cases in which the forensic experts could not clearly establish suicide were excluded. Searches differed between the individual institutes: some had an electronic system in place; in others, the database had to be searched manually. A standardized assessment sheet with sociodemographic aspects and detailed questions on the main suicide methods was used. This instrument had been developed by the research group after a trial period (Habenstein et al. 2013) and contained closed-ended questions on sociodemographic parameters and details for the most common methods of suicide (gas and other intoxications, shooting, drowning, strangulation, thermal trauma, sharp trauma, blunt trauma). Other methods could be specified by writing in an open-ended question. Master’s students, who had all been instructed and tested by the same academic research assistant in order to ascertain interrater reliability, collected data from the 7 institutes of legal and forensic medicine in Switzerland (Basel, Bern, Chur, Geneva, Lausanne, St. Gallen, and Zurich) between spring 2011 and winter 2013. The data were anonymized. Completed questionnaires were transferred to SPSS (IBM, Switzerland) by an automatic scan and were checked manually. For the present study, we extracted all road traffic suicides from the SPSS database of 4,885 suicides, including suicides when driving a vehicle and pedestrian suicides. Suicides by jumping in front of a train were excluded. We used SPSS 20 software to perform frequency analyses and chi-square tests. The significance level (P) was set at .05.
Results Altogether, 76 cases of road traffic suicide were extracted from the whole study population of 4,885 cases (1.56%). Twentythree cases had to be excluded, because they turned out to be cases in which the forensic medical expert suspected that suicide was the manner of death but could not establish it for sure. The manner of suicide was more often uncertain in these
769 Table 1. Sociodemographic parameters of traffic suicide victims Numbers (known cases only) Gender Male Female Age in years∗ (n = 53)
Marital status Unmarried Married Nationality Swiss Other Status/occupation Regular occupation Unemployed Pensioner Other ∗ Indicates
(Percentage)
n = 53 40 13 Range: 18–66 years Median: 43.6 years Average: 41.8 n = 53 40 13 n = 50 38 12 n = 31 23 2 2 4
(75.5) (24.5)
(75.5) (24.5) (76) (24) (74.2) (6.4) (6.4) (12.9)
significant difference using the chi-square test (P < .001).
cases (30.3%) than in the whole SNSF study population; suicide was not firmly established in only 14.6% of cases using other methods (P < .001). The forensic medical experts identified the remaining 53 cases as road traffic suicides. Forty cases (76.9%) underwent a full autopsy, and the rest had external examinations only. Table 1 shows the sociodemographic characteristics of the suicide victims. The age of the road traffic suicide victims was on average 9 years younger than that of the SNSF study population as a whole (53 years, P < .001). As seen in Table 2, most victims died after a collision, mainly with other cars or with trucks and only few were pedestrian suicides. Death most often occurred on a main highway (15 cases), followed by a country road (13 cases). Most victims (64.2%) died of multiple organ failure due to polytraumatic injuries. Testing for alcohol was negative in 24 of all cases, Drug screening was significantly (P < .001) more often negative (41.5%) than in the study population as a whole (16.3%). Acute mental health problems were assumed to be the main reason for suicide in 23 cases. Suicide notes were left less often by traffic suicide victims (20.8%) than by those using other methods (41.8%)—a difference that turned out to be significant (P < .002). Table 2. Details related to the method of traffic suicide Mechanism
n = 33
Collision Pedestrian positioning in front of/under a vehicle (other than a train) Object of collision Car Truck Other Associated deaths of other persons∗ Yes No
24 9
∗ Indicates
(Percentage)
n = 22 10 4 8 n = 53 6 47
significant difference using the chi-square test (P < .001).
(72.7) (27.3)
(45.5) (18.2) (36.3) (11.3) (88.7)
770
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Discussion The present study presents 53 cases of driver suicide, accounting for 1.02% of the 4,885 cases of forensically investigated suicides recorded in Switzerland in the study period. Although 76 cases of driver suicide were identified initially, 30% had to be excluded. Despite suspicions, the forensic expert could not firmly establish suicide as the manner of death in these cases. Our results show that this uncertainty occurred significantly more often in road traffic suicides than in the study group as a whole, which emphasizes the fact that a high proportion of cases cannot be classified and suggests that the proportion of road traffic suicides among road traffic fatalities in Switzerland might actually be higher. Road traffic fatalities where the reasons were totally unclear were not included in our study and therefore do not appear in our statistics. Nor have we included cases that were finally classified as accidents, even though the possibility of suicide had been considered earlier. According to Routley et al. (2003), many road traffic fatalities are never classified as being accidental, suicidal, or natural and remain as open verdicts; as a result, they do not appear in any official statistics at all, even though many studies have suggested that these open verdicts might in fact be suicides. Studies from Ireland and the United States in the 1990s showed that, although the coroner suspected suicide in some of the cases investigated, they were all finally classed as accidents (Conolly et al. 1995; Peck and Warner 1995). In Finland, Ohberg et al. (1997) found a suicide rate of 5.9% for all road fatalities within their study period, whereas the official statistics gave 2.6% in the same period. Regarding the sociodemographic characteristics, our results are mainly in line with other studies on road traffic suicides. All over the world, suicide is more common in men than women. Road traffic suicide, in particular, seems to be committed by a higher proportion of men, usually around 90% (Conolly et al. 1995; Henderson and Joseph 2012; Hernetkoski and Keskinen 1998; Hernetkoski et al. 2009; Milner and de Leo 2012; Murray and de Leo 2007; Routley et al. 2003). Our results showed that the gender ratio was shifted toward men, compared to the SNSF study population as a whole, although the difference was not significant. The mean age of our study population was 9 years younger than that of the whole forensic study population and younger than suicide victims in general, according to the FSO, whose figures show that most suicides are committed between the ages of 45 and 64 years (FSO 2014). This finding agrees with other studies that showed that road traffic suicide victims are generally much younger than those using other suicide methods, with an average age of between 25 and 44 years (Henderson and Joseph 2012; Hernetkoski and Keskinen 1998; Hernetkoski et al. 2009; Milner and de Leo 2012; Murray and de Leo 2007; Ohberg et al. 1997; Routley et al. 2003). Certain diseases, such as cardiovascular diseases, are rare in the younger age group. The question arises whether accidents involving older persons known to have certain medical
Gauthier et al. conditions (coronary artery disease, myocardial infarction, etc.) could not be clearly classified as suicide and were therefore not included in the study group. Most of our suicide victims were unmarried, which is in agreement with the results of other studies (Hernetkoski et al. 2009). Being unmarried is a risk factor for suicide in Switzerland and elsewhere (Prinz and Egger 2014). Three quarters of our suicide cases had a regular occupation, which is in line with other studies finding that road traffic suicide victims are generally employed and have a higher socioeconomic status those using other methods (Milner and de Leo 2012; Murray and de Leo 2007). Murray and de Leo (2007) suggested that this is because there is a good possibility that the suicide will be disguised as an accident, so that relatives do not have to experience the aftermath of a suicide. The manner of suicide in our study was mainly collision, either with other cars or with trucks. Other studies have shown that heavy vehicles, such as trucks, were the counterpart of the collision in most cases (Henderson and Joseph 2012; Hernetkoski et al. 2009; Milner and de Leo 2012; Ohberg et al. 1997). The difference in our study might be explained by the different geographical and road infrastructure. In Switzerland, most trucks drive on the freeways, where the 2 directions of flow are usually separated by central barriers, whereas in other countries, such as Australia, highways are not always divided and huge trucks are common. Only a few collisions were found regarding solid objects, which might be due to the lack of data. Pedestrian suicides were not as common as driver suicides. International studies on pedestrian suicide are scarce. Some studies suggest that pedestrians committing suicide have a history of mental illness (Routley et al. 2003). We could not distinguish whether mental health disorders were more common with pedestrian suicides than with driver suicides because of the small number of cases. Other people are killed significantly more often in association with road traffic suicide than with any other suicide method. Ohberg et al. (1997) found that other persons died in almost 4% of all cases, mainly because truck drivers had lost control and crashed into other vehicles. We did not determine how often other people were seriously hurt but survived and had long-lasting physical or mental problems after the crash. Further studies are needed to determine the resulting effects on health and socioeconomic aspects. Alcohol screening in peripheral blood or muscle and drug screening in urine or kidneys were negative in most of our cases. Other studies have shown that the majority of drivers had drunk alcohol prior to death (Henderson and Joseph 2012; Milner and de Leo 2012; Murray and de Leo 2007; Ohberg et al. 1997; Routley et al. 2003). The abuse of alcohol is also assumed to be a risk factor for suicide and alcohol is commonly taken prior to suicide (Crombie et al. 1998; Pompili et al. 2010), so that this can also be assumed for road traffic suicides. We believe, however, that positive alcohol and/or drug screening might have complicated the assessment of the manner of death for the forensic experts in Switzerland. Because alcohol and drugs are risk factors for road traffic fatalities (WHO 2014), some cases may not have been classed as suicide and therefore not included in our study populations.
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Road Traffic Suicide in Switzerland Suicide notes were left by less than a quarter of all road traffic suicides, significantly fewer than in the study population as a whole. These findings are confirmed by a few other studies, suggesting that suicide in road traffic crashes are mostly impulsive acts (Conolly et al. 1995; Murray and de Leo 2007; Routley et al. 2003). Another explanation might be that suicide notes are not left in order to disguise the suicide as an accident. Prevention strategies are scarce for this deadly method: Because many suicides are said to be impulsive acts (WHO 2014)—something also assumed for road traffic suicide (Conolly et al. 1995; Murray and de Leo 2007; Routley et al. 2003)—restricting access to the means of suicide is an important prevention strategy (Mann et al. 2005; WHO 2014). Unfortunately, this preventive strategy is hardly realistic in the case of road traffic suicide (Routley et al. 2003). New technological developments such as driver assistant systems, anti-collision radars, or intelligent speed adaptation systems might help prevent driver suicide (Hernetkoski et al. 2012; Routley et al. 2003). To prevent pedestrian suicides, Routley et al. (2003) suggested precollision, collision and postcollision strategies for technical devices like pedestrian detection, collision warning systems, and vehicle design. Effective prevention requires detailed knowledge and understanding of the suicide methods used. As international studies have suggested (Milner and de Leo 2012; Murray and de Leo 2007; Routley et al. 2003), every road traffic fatality should be routinely investigated by an interdisciplinary team and suicide should at least be considered at each case. This is already being done in Finland (Hernetkoski and Keskinen 1998), where the suicide in road traffic rate has increased to nearly 10% (Hernetkoski et al. 2012). Psychological autopsy in addition to the forensic autopsy could be helpful to determine whether the traffic fatality was in fact a suicide (Scott et al. 2006). Survivors of road traffic crashes should be routinely examined for suicidal ideation. Road traffic suicides in Switzerland account for approximately 1% of all suicides, though the rate might be higher due to unclassifiable cases. They do not differ from those of other countries regarding sociodemographic parameters or the manner of collision. Given the young age of most road traffic suicide victims, however, we wonder whether road traffic suicide victims are in fact younger than suicides by other methods or whether road traffic fatalities of older people are too difficult to classify as suicides because of comorbid disease. Because road traffic suicides result in other people being killed more often than other suicide methods, this suicide method is highly dangerous to others. Because our study included only those persons who died, further research is needed in this field to assess the health and socioeconomic consequences for seriously injured survivors. Prevention strategies are rare in this seldom-used method. New technological devices such as driver assistant systems may represent one means of method restriction. In the assessment of road traffic crashes, we consider it most important for each case to be routinely investigated by an interdisciplinary team and for suicide to be considered as the cause of the crash in every case.
771 Limitations Due to the retrospective nature of our study, a certain amount of data was not available. The cases were collected by manually searching the databases of the institutes of legal medicine and some of the forensic files do not contain details, such as sociodemographic facts, motives, or psychiatric diseases. In addition, the questionnaire used to collect data for the main SNSF project—Suicides in Switzerland—was initiated to gain more insight into all suicide methods than is provided by the FSO. For this reason as well, certain details on this suicide method were not gathered. Not all suicides in Switzerland during the study period were investigated forensically. A pilot study from Habenstein et al. (2013) found that databases of the Swiss Institutes of legal and forensic medicine usually cover only 34.6% of all suicides. Habenstein et al. (2013) compared data from institute of legal and forensic medicine in Switzerland with FSO data on suicide. They showed that collecting data from the institutes provided the possibility of gaining useful detailed information in a retrospective way, despite the relatively low rate. The proportion of road traffic fatalities investigated forensically might be higher because of the ensuing medico-legal investigation, but the lack of official statistics means that we cannot determine or calculate any rates.
Acknowledgments We thank the directors of the following institutes of legal and forensic medicine in Switzerland for granting access to their case archives: Institute of Forensic Medicine, Bern; Institute of Forensic Medicine, Basel; Institute of Forensic Medicine, St. Gallen; Institute of Pathology and Forensic ¨ Medicine in Graubunden; Institute of Forensic Medicine, Zurich; and Centre universitaire romand de m´edecine l´egale in Geneva and Lausanne. We also thank Dr. Meryl Clarke for linguistic improvement of the article and her critical comments.
References Conolly FJ, Cullen A, McTigue O. Single road traffic deaths—accidents or suicide. Crisis 1995;16(2):85–89. Crombie IK, Punder DJ, Dick PH. Who takes alcohol prior to suicide? J Clin Forensic Med. 1998;5:65–68. Federal Roads Office. Via Secura. Available at: http://www.astra. admin.ch/themen/verkehrssicherheit/00236./ Accessed October 27, 2014. Federal Statistics Office. Verkehrsunf¨alle in der Schweiz. January 20, 2015. Available at: http://www.bfs.admin.ch/bfs/portal/de/index/news/ publikation-en.html?publicationID=5605. Accessed October 6, 2014. Federal Statistics Office. Mortality, causes of death—data, indicators, deaths: numbers, trends and causes. 2014. Available at: http://www.bfs. admin.ch/bfs/portal/en/index/themen/14/02/04/key/01.html. Ac cessed October 6, 2014. Gauthier S, Reisch T, Bartsch C. Self-burning—a rare suicide method in Switzerland and other industrialised nations—a review. Burns. 2014;40(8):1720–1726. Habenstein A, Steffen T, Bartsch C, Michaud K, Reisch T. Chances and limits of method restriction: a detailed analysis of
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772 suicide methods in Switzerland. Arch Suicide Res. 2013;17:75– 87. Henderson AF, Joseph AP. Motor vehicle accident or driver suicide? Identifying cases of failed driver suicide in the trauma setting. Injury. 2012;43:18–21. Hernetkoski K, Keskinen E. Self-destruction in Finnish motor traffic accidents in 1974–1992. Accid Anal Prev. 1998;5:697–704. Hernetkoski KM, Keskinen EO, Parkkari IK. Driver suicides in Finland—are they different in northern and southern Finland? Int J Circumpolar Health. 2009;68:249–259. Mann JJ, Apter A, Bertolote J, et al. Suicide prevention strategies—a systematic review. JAMA. 2005;94:2064–2074. Milner A, de Leo D. Suicide by motor vehicle “accident” in Queensland. Traffic Inj Prev. 2012;13:342–347. Murray D, de Leo D. Suicidal behaviour by motor vehicle collision. Traffic Inj Prev. 2007;8:244–247. Ohberg A, Penttila A, Lonnqvist J. Driver’s suicides. Br J Psychiatry. 1997;171:468–472. Peck D, Warner K. Accident or suicide? Single-vehicle car accidents and the intent hypothesis. Adolescence. 1995;30:463–472.
Gauthier et al. Pompili M, Serafini G, Innamorati M, et al. Suicidal behavior and alcohol abuse. Int J Environ Res Public Health. 2010;7:1392–1431. Prinz S, Egger S. Suizidalit¨at erkennen und beurteilen [Identification and assessment of suicidality]. Praxis. 2014;103:1305–1311. Racioppi F, Eriksson L, Tingvall C, Villaveces A. Preventing Road Traffic Injury: A Public Health Perspective for Europe. World Health Organization; 2004. Available at: http://apps.who.int/iris/handle/10665/ 107554 Routley V, Staines C, Brennan C, Haworth N, Ozanne-Smith J. Suicide and Natural Deaths in Road Traffic—Review. Monash University Accident Research Centre; 2003. Report No. 216. Available at: http://www.monash.edu.au/miri/research/reports/muarc216.html Scott CL, Swartz E, Warburton K. The psychological autopsy: solving mysteries of death. Psychiatr Clin N Am. 2006;29:805–822. Swiss National Science Foundation (SNSF). Suicide in Switzerland: a detailed national survey of the years 2000 to 2010. 2013. Available at: http://p3.snf.ch/Project-133070. Accessed October 6, 2014. World Health Organization. Preventing Suicide: A Global Imperative. Author; 2014. Available at: http://www.who.int/mental health/suicideprevention/world report 2014/en/
ISSN: 1538-9588 (Print) 1538-957X (Online) Journal homepage: http://www.tandfonline.com/loi/gcpi20
Road Traffic Suicide in Switzerland Saskia Gauthier, Thomas Reisch, Vladeta Ajdacic-Gross & Christine Bartsch To cite this article: Saskia Gauthier, Thomas Reisch, Vladeta Ajdacic-Gross & Christine Bartsch (2015) Road Traffic Suicide in Switzerland, Traffic Injury Prevention, 16:8, 768-772, DOI: 10.1080/15389588.2015.1021419 To link to this article: http://dx.doi.org/10.1080/15389588.2015.1021419
Accepted author version posted online: 20 Mar 2015. Published online: 20 Mar 2015. Submit your article to this journal
Article views: 72
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=gcpi20 Download by: [Nanyang Technological University]
Date: 08 November 2015, At: 07:43
Traffic Injury Prevention (2015) 16, 768–772 C Taylor & Francis Group, LLC Copyright ISSN: 1538-9588 print / 1538-957X online DOI: 10.1080/15389588.2015.1021419
Road Traffic Suicide in Switzerland SASKIA GAUTHIER1, THOMAS REISCH2,3, VLADETA AJDACIC-GROSS4, and CHRISTINE BARTSCH1 1
Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland Hospital for Psychiatry, M¨unsingen, Switzerland 3 University Hospital of Psychiatry Bern, Bern, Switzerland 4 University Hospital of Psychiatry, University of Zurich, Switzerland
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2
Received 4 December 2014, Accepted 17 February 2015
Objective: To determine details of road traffic suicides in Switzerland between 2000 and 2010 and to look at our results in relation to studies from other countries. Methods: Retrospective data analysis of road traffic suicides extracted from the database of all suicides investigated by Swiss institutes of forensic medicine between 2000 and 2010 using a standardized assessment sheet. Results: Out of 4,885 suicides in Switzerland, we identified 76 cases (1.56%) of road traffic suicide. Twenty-three cases had to be excluded because, although the forensic medical experts suspected suicide, they could not establish it for sure. That left 53 cases (1.02% of all suicides), mostly unmarried men, who were on average 9 years younger than the study population as a whole. Most collided with other vehicles, mainly other cars, and usually on main highways or country roads. In most cases, the cause of death was multiple injuries. Other persons were killed 4 times more often than with other suicide methods. Toxicology screening was performed significantly more frequently than with other methods but more often proved negative. Acute psychiatric problems were commonly assumed to be the underlying reasons. Suicide notes were left by only 20%, a lower proportion than in the study population as a whole. Conclusions: Road traffic suicides account for approximately 1% of all suicide methods used in Switzerland, although unclassifiable cases indicate that the rate might be higher. Every road traffic crash should therefore be routinely investigated by an interdisciplinary team and suicide should be considered as the possible cause. Keywords: motor vehicle, self-harm, driver suicide, collision, Swiss, forensic, SNSF
Introduction Road traffic injuries and fatalities due to road traffic crashes are a major public health problem worldwide (World Health Organization [WHO] 2004). According to the WHO, approximately 127,000 people die in road traffic accidents each year in Europe (Raciopii et al. 2004). In Switzerland, 269 people died and 21,379 people were injured in this way in 2013 (Federal Statistics Office [FSO] 2014). The Swiss road safety program “Via Secura,” which started in 2013, aims to reduce road traffic fatalities significantly. Its main aspects are awareness of social problems, the behavior of road users, and the safety of motor vehicles and the infrastructure (Federal Roads Office 2014). Suicide in road traffic is not part of Via Secura, although international studies have found evidence that road traffic suicides are underestimated because they are often misinterpreted as accidents (Murray and de Leo 2007; Ohberg
Managing Editor David Viano oversaw the review of this article. Address correspondence to Saskia Gauthier, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190 8057, Zurich, Switzerland. E-mail: [email protected]
et al. 1997; Routley et al. 2003). It is assumed that 1–7% of all road traffic fatalities are really suicides (Routley et al. 2003). In Switzerland, 1,037 people died by suicide in 2012, making this the leading cause of nonnatural deaths. Hanging, shooting, and intoxication were the most commonly used methods (FSO 2014), but official statistics provide no data on suicide in traffic. The present study is part of a large-scale research project founded by the Swiss National Science Foundation (SNSF). The overall aim is to obtain more detailed knowledge about suicide methods than is provided by the FSO, with the objective of developing new prevention strategies based on the newly acquired information. From the data pool of 4,885 suicides (SNSF 2013), we extracted road traffic suicides, including collisions and pedestrian suicides, with the following aims: 1. To determine details of suicide in traffic in Switzerland and to look at our results in relation to studies from other countries. 2. To compare selected aspects of road traffic suicide with data from the other suicide methods in Switzerland, in order to determine any possible differences.
Road Traffic Suicide in Switzerland
Downloaded by [Nanyang Technological University] at 07:43 08 November 2015
Methods The present study consisted of a retrospective data analysis of suicides in road traffic investigated forensically, using a standardized assessment sheet. The data collection methods were identical to those described by the authors in “Self-Burning, a Rare Suicide Method in Switzerland and Other Industrialized Nations—A Review” (Gauthier et al. 2014), with the exception that the cases extracted were road traffic suicides. This study is also part of the SNSF project Suicide in Switzerland: A Detailed National Survey of the Years 2000 to 2010, which retrospectively examined all cases of completed suicide that had been investigated, with a full autopsy or simple external examination, by institutes of legal and forensic medicine in Switzerland. The databases of all of these institutes were searched for suicides occurring in the period 2000–2010 and 4,885 cases were included. In Switzerland, forensic medical examiners define the manner of death after having performed their examinations (external examination and/or autopsy and additional analysis, such as toxicological) usually in combination with results of police investigation. Only those cases where suicide was the definite manner of death were included. Cases in which the forensic experts could not clearly establish suicide were excluded. Searches differed between the individual institutes: some had an electronic system in place; in others, the database had to be searched manually. A standardized assessment sheet with sociodemographic aspects and detailed questions on the main suicide methods was used. This instrument had been developed by the research group after a trial period (Habenstein et al. 2013) and contained closed-ended questions on sociodemographic parameters and details for the most common methods of suicide (gas and other intoxications, shooting, drowning, strangulation, thermal trauma, sharp trauma, blunt trauma). Other methods could be specified by writing in an open-ended question. Master’s students, who had all been instructed and tested by the same academic research assistant in order to ascertain interrater reliability, collected data from the 7 institutes of legal and forensic medicine in Switzerland (Basel, Bern, Chur, Geneva, Lausanne, St. Gallen, and Zurich) between spring 2011 and winter 2013. The data were anonymized. Completed questionnaires were transferred to SPSS (IBM, Switzerland) by an automatic scan and were checked manually. For the present study, we extracted all road traffic suicides from the SPSS database of 4,885 suicides, including suicides when driving a vehicle and pedestrian suicides. Suicides by jumping in front of a train were excluded. We used SPSS 20 software to perform frequency analyses and chi-square tests. The significance level (P) was set at .05.
Results Altogether, 76 cases of road traffic suicide were extracted from the whole study population of 4,885 cases (1.56%). Twentythree cases had to be excluded, because they turned out to be cases in which the forensic medical expert suspected that suicide was the manner of death but could not establish it for sure. The manner of suicide was more often uncertain in these
769 Table 1. Sociodemographic parameters of traffic suicide victims Numbers (known cases only) Gender Male Female Age in years∗ (n = 53)
Marital status Unmarried Married Nationality Swiss Other Status/occupation Regular occupation Unemployed Pensioner Other ∗ Indicates
(Percentage)
n = 53 40 13 Range: 18–66 years Median: 43.6 years Average: 41.8 n = 53 40 13 n = 50 38 12 n = 31 23 2 2 4
(75.5) (24.5)
(75.5) (24.5) (76) (24) (74.2) (6.4) (6.4) (12.9)
significant difference using the chi-square test (P < .001).
cases (30.3%) than in the whole SNSF study population; suicide was not firmly established in only 14.6% of cases using other methods (P < .001). The forensic medical experts identified the remaining 53 cases as road traffic suicides. Forty cases (76.9%) underwent a full autopsy, and the rest had external examinations only. Table 1 shows the sociodemographic characteristics of the suicide victims. The age of the road traffic suicide victims was on average 9 years younger than that of the SNSF study population as a whole (53 years, P < .001). As seen in Table 2, most victims died after a collision, mainly with other cars or with trucks and only few were pedestrian suicides. Death most often occurred on a main highway (15 cases), followed by a country road (13 cases). Most victims (64.2%) died of multiple organ failure due to polytraumatic injuries. Testing for alcohol was negative in 24 of all cases, Drug screening was significantly (P < .001) more often negative (41.5%) than in the study population as a whole (16.3%). Acute mental health problems were assumed to be the main reason for suicide in 23 cases. Suicide notes were left less often by traffic suicide victims (20.8%) than by those using other methods (41.8%)—a difference that turned out to be significant (P < .002). Table 2. Details related to the method of traffic suicide Mechanism
n = 33
Collision Pedestrian positioning in front of/under a vehicle (other than a train) Object of collision Car Truck Other Associated deaths of other persons∗ Yes No
24 9
∗ Indicates
(Percentage)
n = 22 10 4 8 n = 53 6 47
significant difference using the chi-square test (P < .001).
(72.7) (27.3)
(45.5) (18.2) (36.3) (11.3) (88.7)
770
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Discussion The present study presents 53 cases of driver suicide, accounting for 1.02% of the 4,885 cases of forensically investigated suicides recorded in Switzerland in the study period. Although 76 cases of driver suicide were identified initially, 30% had to be excluded. Despite suspicions, the forensic expert could not firmly establish suicide as the manner of death in these cases. Our results show that this uncertainty occurred significantly more often in road traffic suicides than in the study group as a whole, which emphasizes the fact that a high proportion of cases cannot be classified and suggests that the proportion of road traffic suicides among road traffic fatalities in Switzerland might actually be higher. Road traffic fatalities where the reasons were totally unclear were not included in our study and therefore do not appear in our statistics. Nor have we included cases that were finally classified as accidents, even though the possibility of suicide had been considered earlier. According to Routley et al. (2003), many road traffic fatalities are never classified as being accidental, suicidal, or natural and remain as open verdicts; as a result, they do not appear in any official statistics at all, even though many studies have suggested that these open verdicts might in fact be suicides. Studies from Ireland and the United States in the 1990s showed that, although the coroner suspected suicide in some of the cases investigated, they were all finally classed as accidents (Conolly et al. 1995; Peck and Warner 1995). In Finland, Ohberg et al. (1997) found a suicide rate of 5.9% for all road fatalities within their study period, whereas the official statistics gave 2.6% in the same period. Regarding the sociodemographic characteristics, our results are mainly in line with other studies on road traffic suicides. All over the world, suicide is more common in men than women. Road traffic suicide, in particular, seems to be committed by a higher proportion of men, usually around 90% (Conolly et al. 1995; Henderson and Joseph 2012; Hernetkoski and Keskinen 1998; Hernetkoski et al. 2009; Milner and de Leo 2012; Murray and de Leo 2007; Routley et al. 2003). Our results showed that the gender ratio was shifted toward men, compared to the SNSF study population as a whole, although the difference was not significant. The mean age of our study population was 9 years younger than that of the whole forensic study population and younger than suicide victims in general, according to the FSO, whose figures show that most suicides are committed between the ages of 45 and 64 years (FSO 2014). This finding agrees with other studies that showed that road traffic suicide victims are generally much younger than those using other suicide methods, with an average age of between 25 and 44 years (Henderson and Joseph 2012; Hernetkoski and Keskinen 1998; Hernetkoski et al. 2009; Milner and de Leo 2012; Murray and de Leo 2007; Ohberg et al. 1997; Routley et al. 2003). Certain diseases, such as cardiovascular diseases, are rare in the younger age group. The question arises whether accidents involving older persons known to have certain medical
Gauthier et al. conditions (coronary artery disease, myocardial infarction, etc.) could not be clearly classified as suicide and were therefore not included in the study group. Most of our suicide victims were unmarried, which is in agreement with the results of other studies (Hernetkoski et al. 2009). Being unmarried is a risk factor for suicide in Switzerland and elsewhere (Prinz and Egger 2014). Three quarters of our suicide cases had a regular occupation, which is in line with other studies finding that road traffic suicide victims are generally employed and have a higher socioeconomic status those using other methods (Milner and de Leo 2012; Murray and de Leo 2007). Murray and de Leo (2007) suggested that this is because there is a good possibility that the suicide will be disguised as an accident, so that relatives do not have to experience the aftermath of a suicide. The manner of suicide in our study was mainly collision, either with other cars or with trucks. Other studies have shown that heavy vehicles, such as trucks, were the counterpart of the collision in most cases (Henderson and Joseph 2012; Hernetkoski et al. 2009; Milner and de Leo 2012; Ohberg et al. 1997). The difference in our study might be explained by the different geographical and road infrastructure. In Switzerland, most trucks drive on the freeways, where the 2 directions of flow are usually separated by central barriers, whereas in other countries, such as Australia, highways are not always divided and huge trucks are common. Only a few collisions were found regarding solid objects, which might be due to the lack of data. Pedestrian suicides were not as common as driver suicides. International studies on pedestrian suicide are scarce. Some studies suggest that pedestrians committing suicide have a history of mental illness (Routley et al. 2003). We could not distinguish whether mental health disorders were more common with pedestrian suicides than with driver suicides because of the small number of cases. Other people are killed significantly more often in association with road traffic suicide than with any other suicide method. Ohberg et al. (1997) found that other persons died in almost 4% of all cases, mainly because truck drivers had lost control and crashed into other vehicles. We did not determine how often other people were seriously hurt but survived and had long-lasting physical or mental problems after the crash. Further studies are needed to determine the resulting effects on health and socioeconomic aspects. Alcohol screening in peripheral blood or muscle and drug screening in urine or kidneys were negative in most of our cases. Other studies have shown that the majority of drivers had drunk alcohol prior to death (Henderson and Joseph 2012; Milner and de Leo 2012; Murray and de Leo 2007; Ohberg et al. 1997; Routley et al. 2003). The abuse of alcohol is also assumed to be a risk factor for suicide and alcohol is commonly taken prior to suicide (Crombie et al. 1998; Pompili et al. 2010), so that this can also be assumed for road traffic suicides. We believe, however, that positive alcohol and/or drug screening might have complicated the assessment of the manner of death for the forensic experts in Switzerland. Because alcohol and drugs are risk factors for road traffic fatalities (WHO 2014), some cases may not have been classed as suicide and therefore not included in our study populations.
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Road Traffic Suicide in Switzerland Suicide notes were left by less than a quarter of all road traffic suicides, significantly fewer than in the study population as a whole. These findings are confirmed by a few other studies, suggesting that suicide in road traffic crashes are mostly impulsive acts (Conolly et al. 1995; Murray and de Leo 2007; Routley et al. 2003). Another explanation might be that suicide notes are not left in order to disguise the suicide as an accident. Prevention strategies are scarce for this deadly method: Because many suicides are said to be impulsive acts (WHO 2014)—something also assumed for road traffic suicide (Conolly et al. 1995; Murray and de Leo 2007; Routley et al. 2003)—restricting access to the means of suicide is an important prevention strategy (Mann et al. 2005; WHO 2014). Unfortunately, this preventive strategy is hardly realistic in the case of road traffic suicide (Routley et al. 2003). New technological developments such as driver assistant systems, anti-collision radars, or intelligent speed adaptation systems might help prevent driver suicide (Hernetkoski et al. 2012; Routley et al. 2003). To prevent pedestrian suicides, Routley et al. (2003) suggested precollision, collision and postcollision strategies for technical devices like pedestrian detection, collision warning systems, and vehicle design. Effective prevention requires detailed knowledge and understanding of the suicide methods used. As international studies have suggested (Milner and de Leo 2012; Murray and de Leo 2007; Routley et al. 2003), every road traffic fatality should be routinely investigated by an interdisciplinary team and suicide should at least be considered at each case. This is already being done in Finland (Hernetkoski and Keskinen 1998), where the suicide in road traffic rate has increased to nearly 10% (Hernetkoski et al. 2012). Psychological autopsy in addition to the forensic autopsy could be helpful to determine whether the traffic fatality was in fact a suicide (Scott et al. 2006). Survivors of road traffic crashes should be routinely examined for suicidal ideation. Road traffic suicides in Switzerland account for approximately 1% of all suicides, though the rate might be higher due to unclassifiable cases. They do not differ from those of other countries regarding sociodemographic parameters or the manner of collision. Given the young age of most road traffic suicide victims, however, we wonder whether road traffic suicide victims are in fact younger than suicides by other methods or whether road traffic fatalities of older people are too difficult to classify as suicides because of comorbid disease. Because road traffic suicides result in other people being killed more often than other suicide methods, this suicide method is highly dangerous to others. Because our study included only those persons who died, further research is needed in this field to assess the health and socioeconomic consequences for seriously injured survivors. Prevention strategies are rare in this seldom-used method. New technological devices such as driver assistant systems may represent one means of method restriction. In the assessment of road traffic crashes, we consider it most important for each case to be routinely investigated by an interdisciplinary team and for suicide to be considered as the cause of the crash in every case.
771 Limitations Due to the retrospective nature of our study, a certain amount of data was not available. The cases were collected by manually searching the databases of the institutes of legal medicine and some of the forensic files do not contain details, such as sociodemographic facts, motives, or psychiatric diseases. In addition, the questionnaire used to collect data for the main SNSF project—Suicides in Switzerland—was initiated to gain more insight into all suicide methods than is provided by the FSO. For this reason as well, certain details on this suicide method were not gathered. Not all suicides in Switzerland during the study period were investigated forensically. A pilot study from Habenstein et al. (2013) found that databases of the Swiss Institutes of legal and forensic medicine usually cover only 34.6% of all suicides. Habenstein et al. (2013) compared data from institute of legal and forensic medicine in Switzerland with FSO data on suicide. They showed that collecting data from the institutes provided the possibility of gaining useful detailed information in a retrospective way, despite the relatively low rate. The proportion of road traffic fatalities investigated forensically might be higher because of the ensuing medico-legal investigation, but the lack of official statistics means that we cannot determine or calculate any rates.
Acknowledgments We thank the directors of the following institutes of legal and forensic medicine in Switzerland for granting access to their case archives: Institute of Forensic Medicine, Bern; Institute of Forensic Medicine, Basel; Institute of Forensic Medicine, St. Gallen; Institute of Pathology and Forensic ¨ Medicine in Graubunden; Institute of Forensic Medicine, Zurich; and Centre universitaire romand de m´edecine l´egale in Geneva and Lausanne. We also thank Dr. Meryl Clarke for linguistic improvement of the article and her critical comments.
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