- Email: [email protected]
Motor vehicle accident or driver suicide? Identifying cases of failed driver suicide in the trauma setting
Injury, Int. J. Care Injured 43 (2012) 18–21
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Review
Motor vehicle accident or driver suicide? Identifying cases of failed driver suicide in the trauma setting Antony F. Henderson a,*, Anthony P. Joseph b,c a b
Department of Surgery, Royal North Shore Hospital, Reserve Rd, St Leonards NSW 2065, Sydney, Australia Emergency Department, Royal North Shore Hospital, Sydney Medical School, University of Sydney, Royal North Shore Hospital, Reserve Rd, St Leonards NSW 2065, Sydney, Australia
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 21 June 2011
Many authors have suggested that some road traffic crashes are disguised suicide attempts. A case report and literature review is used to explore this claim and to examine the frequency and risk factors associated with driver suicide. The author concludes the methodological difficulty of establishing the driver’s intent of suicide accounts for an under-estimation of the frequency of this event and that many cases of driver suicide go unrecognised. Familiarity with the risk factors associated with driver suicide may assist in the identification of cases of failed driver suicide and referral to psychiatric services. ß 2011 Elsevier Ltd. All rights reserved.
Keywords: Trauma Suicide Driver suicide Suicide Self-inflicted injury Deliberate crash Intentional crash
Contents Introduction . . . . . . . . . . . . . . Clinical record . . . . . . . . . . . . A review of the literature . . . Risk factors for driver suicide Discussion . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . Acknowledgements . . . . . . . . References . . . . . . . . . . . . . . .
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18 18 19 20 20 20 20 20
Introduction Suicide research has not considered motor vehicle crashes to be a common method. This is likely to be due to the difficulty in recognizing cases of driver suicide, or attempted driver suicide, in contradistinction to methods of suicide whereby intent is selfevident, such as in hanging. Studies exploring driver suicide are faced with the inherent difficulty of establishing the driver’s suicide intent. In cases of attempted driver suicide, establishing the intent to suicide is difficult by virtue of non-disclosure. These methodological difficulties suggest suicide and attempted suicide by motor vehicle crash may be more common than is recognized in clinical practice and the literature. A case review and review of the literature is used to examine the risk factors associated with driver suicide and to explore its likely prevalence. * Corresponding author. Tel.: +61 2 99267111; mobile: +61 421 498 338. E-mail addresses: [email protected] (A.F. Henderson), [email protected] (A.P. Joseph). c Tel.: +61 2 9926 5151; mobile: +61 411 265 870. 0020–1383/$ – see front matter ß 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2011.06.192
Clinical record A previously healthy 31-year-old man was brought by ambulance to the emergency department of a New South Wales
A.F. Henderson, A.P. Joseph / Injury, Int. J. Care Injured 43 (2012) 18–21
tertiary referral hospital following a motor vehicle accident. The man claimed to have lost control of his vehicle and crashed into a tree approximately 70 km/h. He was wearing a seat belt and airbags had been deployed. The motor vehicle was significantly deformed with an extrication time of 1 h. The patient denied losing consciousness, having fallen asleep and having used alcohol. He had a zero blood alcohol level on formal testing. Following an assessment in the emergency department, the patient was found to have a seat belt abrasion to his left shoulder and an abrasion to his left elbow, but was otherwise relatively unharmed. The elbow abrasions contained a piece of glass which was later operatively removed. Following the operation, the hospital Trauma Service, which included a psychiatrist training as a surgeon, conducted a tertiary survey of the patient on the ward and questioned him regarding the circumstances of the accident. The crash had occurred in the early afternoon during fair weather. The patient stated that he was unable to negotiate a bend in the road and consequently crashed his motor vehicle. The patient stated he had just dropped off his daughter at his wife’s house, from whom he had recently separated, and was heading home. The patient said he had been struggling since the separation, appeared distressed, then said: ‘‘I couldn’t see the point in going on...I saw a group of trees ahead, at the curve in the road – I aimed for the largest one and accelerated’’. The patient agreed to undergo a psychiatric assessment prior to his discharge. The motor vehicle accident was assessed to have been the result of an impulsive suicide attempt, in the context of an adjustment disorder, precipitated by his marital break-up. He was also assessed to have personality vulnerabilities related to selfesteem and difficulties in coping with rejection. This was thought to be related to the reported death of his mother at an early age, which left him in the care of a violent and alcoholic father. The separation from his wife was suggested to have activated unresolved grief surrounding the loss of his mother, leading to feelings of intense despair and suicidal impulses. The patient was not found to have ongoing suicidal ideation and agreed to a followup with psychiatric services upon discharge. This case illustrates the situation whereby most trauma cases are assumed to be the result of an ‘accident’. However the doctor performing the tertiary survey became suspicious of the intentionality of the incident when the patient described favourable driving conditions and that he had been ‘‘under a lot of stress lately’’. Further exploration by the doctor allowed the patient to disclose his intent to commit suicide.
A review of the literature Motor vehicle collision is the leading cause of traumatic death worldwide1 and accounts for 45% of all hospital trauma admissions.2 The World Health Organization (WHO) estimated over 1.3 million people are killed in motor vehicle collisions each year with up to 50 million non-fatal injuries.3 The mortality rate for males is three times higher than for females and more than 50% of the mortality from motor vehicle collisions occurs in young adults (ages 15–44). The global economic cost of road traffic injuries, including medical treatment and loss of productivity, is estimated to be US$ 518 billion per annum. For each country, this typically represents between 1% and 3% of the gross national product per annum.4 Despite the availability, familiarity and lethality of motor vehicles, as well as the potential for concealing the intention, suicide by motor vehicle crash has not been recognized as a common method of suicide. World Health Organization (WHO) has estimated 0.2% of all cases of suicide are the result of motor vehicle crash.5
19
A literature review on driver suicide by Routley et al. in 2003,6 examined 13 studies from different countries and found a substantial range in the reported incidence of driver suicide, with figures ranging from 1.1% to 7.4% of all motor vehicle collisions. This variance is likely due to the methodological difficulties in establishing suicide intent. Unlike other methods of suicide, such as hanging and carbon monoxide poisoning where ascertainment of intent is high, it is very difficult to establish intent of suicide in motor vehicle collisions. The studies aim to determine suicide intent by examining the physical evidence from the crash scene, such as skid marks, or lack thereof, to estimate vehicle speed or evidence of attempted collision aversion. Witnesses and relatives of the deceased are interviewed and pathology, autopsy, medical, police and coronal reports are examined in attempt to identify factors that may suggest suicide, such as recent life stressors, changes in mental state, drug or alcohol use and previous attempts or threats of suicide. The quality of the data obtained to determine intent of suicide is largely dependent on the resources of the investigating agencies of each region. The criteria used to establish a driver fatality as suicide also varied between studies. Regional religious, cultural and legal differences may also influence the completeness and accuracy of information disclosure and suicide classification. For example, the suicide rates in Roman Catholic or Moslem countries is considered to be low, however it is unclear if this reflects a true influence of religion on behaviour or is the result of systematic underreporting.7 Despite the wide variance of incidence of reported suicide, the reported rates of driver suicide have been found to be higher than official reports. A study by Ohberg et al.,8 reporting the largest number of driver fatalities (n = 1419), found 5.9% (n = 84) of driver fatalities were driver suicide. Official statistics based on the death certificates classified 2.6% (n = 37) of the fatalities as suicides, suggesting a misclassification of more than half the cases of driver suicides. Since the review by Routley et al. (2003)6, there have been six further publications relating to driver suicide. The largest and most recent study to date on driver suicide is a Finnish study by Hernetkoski et al.9 who examined 3508 fatal motor vehicle accidents during the years 1974–2006 and found 6.5% (n = 227) of cases were driver suicide. It also found the rate of driver suicide increased to 9–10% over the years 2005–2006. Bjornstig et al.10 examined 293 passenger car occupants killed in collisions with other vehicles and found 13 (4.4%) were likely to be suicides. However, this study may have underestimated the prevalence of driver suicide as the literature suggests driver suicides are more likely to be the result of single-vehicle accidents.11 A case–control study by Lam et al.12 examined the association between suicidal ideation and risk of car crash injuries. Self-reported information on suicidal ideation was collected in 571 injured motor vehicle drivers presenting to hospital and a control group of 588 uninjured drivers. The prevalence of suicidal ideation over the preceding 12 months was found to be higher in the injured driver group than the control drivers, suggesting suicidal ideation was associated with driver injury. However, this association was not present when examining drivers with a history of suicidal ideation who were taking antidepressant medication. A similarly designed study by Pompili et al.13 compared the suicide intent in 30 single-car accident drivers admitted to hospital and matched control drivers who had never had a car accident. Both groups were administered a Reason for Living (RFL) questionnaire,14 which investigated the participants attitudes to suicide. The study found single-car accident drivers scored lower on the RFL questionnaire than the driver control group, suggesting the single-car accident drivers had more ambivalence about living. Although these patients were not overtly suicidal, the author concluded ambivalence about living
A.F. Henderson, A.P. Joseph / Injury, Int. J. Care Injured 43 (2012) 18–21
20
might translate into excessive risk taking, self-neglect and risk of motor vehicle injury. The WHO/EURO Multicentre Study on Parasuicide (2000) by Michel et al.5 is the largest study to date examining the frequencies of different methods of attempted suicide. The study analysed 25,816 suicide attempts across 12 European countries over a 4year period and recorded 62 cases of attempted suicide by motor vehicle crash, representing 0.2% of all cases of attempted suicides. This study suggests motor vehicle crash is the 12th most common method of attempted suicide. However, Murray et al.15 performed a random postal survey of 8677 individuals in an urban geographic region in Australia to identify individuals with a lifetime history of suicidal ideation or attempt. 412 individuals were identified to have a history of suicidal ideation, of which 14.8% (n = 61) had planned or made arrangements to suicide by crashing a motor vehicle. 228 individuals were identified to have made a suicide attempt, of which 8.3% (n = 19) were attempts by driver suicide. According to the distribution of methods of suicide in the study by Michel et al.,5 this would then place attempted suicide by motor vehicle crash as the second most common method of attempted suicide after drug and alcohol overdose. The differences in the results of these two studies could be explained by the different methodological approaches employed. The Murray et al. study surveyed the life-time history of attempted suicide by motor vehicle crash in a community sample by posting a questionnaire, which may be less confronting and may result in higher rates of disclosure of attempted driver suicide. Whereas, the WHO study relied on participants disclosing their intent of driver suicide in the course of a hospital admission for their injuries. However, the Murray et al. study has a relatively small sample size from a small geographic area thus limiting the generalisability of these results.
Risk factors for driver suicide The current literature has identified specific factors associated with driver suicide (Table 1). In 2008 the Australian Bureau of Statistics had recorded 126 cases of deliberate crashing of a motor vehicle over the previous 10 years.16 The majority were males (82.5%) in the younger age group (17.5% between 20 and 24 yearsof-age). Most driver suicides result from single vehicle crashes,11 however if another vehicle is involved, it is usually a heavy vehicle or truck10; improved modern car safety features may lead to the perception that crashing into an oncoming heavy goods vehicle is a more lethal crash target than a stationary object. Alcohol intoxication has also been implicated in driver suicide, with one study showing 79% of cases of driver suicide had used alcohol at the time of the accident.17 Depression and prior suicide attempts have also been shown to be related to driver suicide. In interviews of relatives of driver suicide victims by Hernetkoski et al.,18 48% of suicide victims suffered depression.
Discussion Road safety measures such as matching speed limits to driving conditions, greater investment in road infrastructure and campaigns against driver fatigue, drink driving and the non-wearing of seat belts have contributed to a reduction in road deaths over the last 5 years.4 However many national road safety strategies have failed to reach their target reduction in road fatality rate. Of particular concern, the road fatality rate has remained relatively static for the young/male group. One possible explanation for this is that a significant proportion of these accidents are unrecognised suicide attempts. The introduction of a nationally standardized assessment of motor vehicle crashes that cannot be readily explained, including examination of the accident site and of the victim’s psychosocial circumstances, is required to improve the ascertainment of driver suicide. Once the prevalence of driver suicide is more clearly established, the introduction of specific driver suicide prevention strategies, such as anti-collision radar (that automatically engages the brakes if an obstacle is detected) and alcohol interlock systems, may be considered to further reduce the road fatality rate. Hospital emergency department and trauma staff are in a unique position to identify cases of undisclosed attempted driver suicide. Clinical staff with an awareness of the likely frequency and familiarity with the risk factors associated the driver suicide (e.g. young, male, and single occupant vehicle) will increase the recognition and disclosure of cases of attempted driver suicide. This assessment may be formalised by its incorporation in the tertiary trauma survey.19 This assessment may consist of questions surrounding the injury circumstances, and consideration of the patient’s risk factors for driver suicide. If the patient’s replies are considered vague or inconsistent and significant risk factors are present, more direct questions regarding injury intentionality may be warranted. Conclusion Research into driver suicide is relatively sparse because of the methodological difficulties associated with establishing the intent of suicide in cases of motor vehicle crashes. Despite this, the current literature would suggest that at least 1 in 15 motor vehicle crashes are intentional and remain largely unrecognised. The literature also suggests specific crash circumstances and driver socio-demographic background factors are associated with driver suicide. Formally assessing the risk factors associated with driver suicide may increase the identification of failed driver suicide and referral to psychiatric services. This will have implications for secondary suicide prevention and ongoing medical costs. Conflict of interest statement There are no conflicts of interest in the writing and publication of this paper.
Table 1 Risk factors associated with driver suicides.
Males. Age between 25 and 34. Single occupant crash. Non-wearing of a seat belt. Head-on collision. Single vehicle crash (into a tree or pole). Collision into a heavy goods vehicle. Absence of skid marks or other evidence for loss of control over the vehicle. Alcohol intoxication/abuse. Significant recent psychosocial stress. Mental disorders (such as depression) and previous suicide attempt. Impulsivity and low distress tolerance personality trait.
Acknowledgements The author thanks Conor Sherry and Janan Karatas, PhD for editorial assistance. References 1. The top 10 leading causes of death (Fact Sheet No. 310). Geneva: World Health Organization; 2008. Available from: http://www.who.int/mediacentre/factsheets/fs310/en/ [accessed 16.05.11]. 2. Roudsari BS, Sharzei K, Zargar M. Sex and age distribution in transport related injuries in Tehran. Accid Anal Prev 2004;36:391–8.
A.F. Henderson, A.P. Joseph / Injury, Int. J. Care Injured 43 (2012) 18–21 3. World Health Organization. The UN tackles road safety (Note for the media). 3 March 2010. Available from: http://www.who.int/mediacentre/news/notes/ 2010/traffic_injuries_media_20100303/en/index.html [accessed 16.05.11]. 4. United Nations General Assembly Report of the Secretary-General. Global Road Safety Crisis. 7 August 2003. Available from: http://www.searo.who.int/LinkFiles/ whd04_Documents_un_secretary_general_report_on_orad_traffic_injuries.pdf. 5. Michel K, Ballinari P, Bille-Brahe U, Bjerke T, Crepet P, De Leo D. Methods used for parasuicide: results of the WHO/EURO Multicentre Study on Parasuicide. Soc Psychiatry Psychiatr Epidemiol 2000;35(4):156–63. 6. Routley V, Staines C, Brennan C, Haworth N, Ozanne-Smith J. Suicide and natural deaths in road traffic – review, August Report no. 216 (2003). Monash University Accident Research Centre, Melbourne, Australia. 7. Huang W, Religion. culture, economic and sociological correlates of suicide rates: a cross-national analysis. Appl Econ Lett 1996;3(12):779–82. 8. Ohberg A, Penttila A, Lonnqvist J. Driver suicides. Br J Psychiatry 1997;171:468–72. 9. Hernetkoski K, Keskinen E, Parkkari I. Driver suicides in Finland—are they different in northern and southern Finland? Int J Circumpolar Health 2009;68(3):249–60. 10. Bjornstig U, Bjornstig J, Eriksson A. Passenger car collision fatalities—with special emphasis on collisions with heavy vehicles. Accid Anal Prevention 2008;40(1):158–66.
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11. Peck DL, Warner K. Accident or suicide? Single-vehicle car accidents and the intent hypothesis. Adolescence 1995;30(118):463–72. 12. Lam LT, Norton R, Connor J, Ameratunga S. Suicidal ideation, antidepressive medication and car crash injury. Accid Anal Prev 2005;37(2):335–9. 13. Pompili M, Girardi P, Tatarelli G, Tatarelli R. Suicidal intent in single-car accident drivers: review and new preliminary findings. Crisis 2006;27(2):92–9. 14. Lineham MM, Goodstein JL, Nielson SL, Chiles JA. Reasons for staying alive when you are thinking of killing yourself: the reason for living inventory. J Consult Clin Psych 1983;51(2):276–86. 15. Murray D, de Leo D. Suicide behavior by motor vehicle collision. Traffic Inj Prev 2007;8(3):244–7. 16. Australian Bureau of Statistics. Causes of Death, Australia, 2008. Available from: http://www.abs.gov.au/ausstats/[email protected]/Products/3392C53D12E8C51ACA2576F6001246CA?opendocument [accessed 14.05.11]. 17. Australian Transport Council. Draft National Road Safety Strategy 2011–2020. Available from: http://www.atcouncil.gov.au/documents/atcnrss.aspx [accessed 12.05.11]. 18. Hernetkoski K, Keskinen E. Self-destruction in Finnish motor traffic accidents in 1974–1992. Accid Anal Prev 1998;30(5):697–704. 19. Enderson B, Reath D, Meadors J, Dallas W, DeBoo J, Maull K. The tertiary trauma survey: a prospective study of missed injury. J Trauma 1990;30:666–70.
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Review
Motor vehicle accident or driver suicide? Identifying cases of failed driver suicide in the trauma setting Antony F. Henderson a,*, Anthony P. Joseph b,c a b
Department of Surgery, Royal North Shore Hospital, Reserve Rd, St Leonards NSW 2065, Sydney, Australia Emergency Department, Royal North Shore Hospital, Sydney Medical School, University of Sydney, Royal North Shore Hospital, Reserve Rd, St Leonards NSW 2065, Sydney, Australia
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 21 June 2011
Many authors have suggested that some road traffic crashes are disguised suicide attempts. A case report and literature review is used to explore this claim and to examine the frequency and risk factors associated with driver suicide. The author concludes the methodological difficulty of establishing the driver’s intent of suicide accounts for an under-estimation of the frequency of this event and that many cases of driver suicide go unrecognised. Familiarity with the risk factors associated with driver suicide may assist in the identification of cases of failed driver suicide and referral to psychiatric services. ß 2011 Elsevier Ltd. All rights reserved.
Keywords: Trauma Suicide Driver suicide Suicide Self-inflicted injury Deliberate crash Intentional crash
Contents Introduction . . . . . . . . . . . . . . Clinical record . . . . . . . . . . . . A review of the literature . . . Risk factors for driver suicide Discussion . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . Acknowledgements . . . . . . . . References . . . . . . . . . . . . . . .
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18 18 19 20 20 20 20 20
Introduction Suicide research has not considered motor vehicle crashes to be a common method. This is likely to be due to the difficulty in recognizing cases of driver suicide, or attempted driver suicide, in contradistinction to methods of suicide whereby intent is selfevident, such as in hanging. Studies exploring driver suicide are faced with the inherent difficulty of establishing the driver’s suicide intent. In cases of attempted driver suicide, establishing the intent to suicide is difficult by virtue of non-disclosure. These methodological difficulties suggest suicide and attempted suicide by motor vehicle crash may be more common than is recognized in clinical practice and the literature. A case review and review of the literature is used to examine the risk factors associated with driver suicide and to explore its likely prevalence. * Corresponding author. Tel.: +61 2 99267111; mobile: +61 421 498 338. E-mail addresses: [email protected] (A.F. Henderson), [email protected] (A.P. Joseph). c Tel.: +61 2 9926 5151; mobile: +61 411 265 870. 0020–1383/$ – see front matter ß 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2011.06.192
Clinical record A previously healthy 31-year-old man was brought by ambulance to the emergency department of a New South Wales
A.F. Henderson, A.P. Joseph / Injury, Int. J. Care Injured 43 (2012) 18–21
tertiary referral hospital following a motor vehicle accident. The man claimed to have lost control of his vehicle and crashed into a tree approximately 70 km/h. He was wearing a seat belt and airbags had been deployed. The motor vehicle was significantly deformed with an extrication time of 1 h. The patient denied losing consciousness, having fallen asleep and having used alcohol. He had a zero blood alcohol level on formal testing. Following an assessment in the emergency department, the patient was found to have a seat belt abrasion to his left shoulder and an abrasion to his left elbow, but was otherwise relatively unharmed. The elbow abrasions contained a piece of glass which was later operatively removed. Following the operation, the hospital Trauma Service, which included a psychiatrist training as a surgeon, conducted a tertiary survey of the patient on the ward and questioned him regarding the circumstances of the accident. The crash had occurred in the early afternoon during fair weather. The patient stated that he was unable to negotiate a bend in the road and consequently crashed his motor vehicle. The patient stated he had just dropped off his daughter at his wife’s house, from whom he had recently separated, and was heading home. The patient said he had been struggling since the separation, appeared distressed, then said: ‘‘I couldn’t see the point in going on...I saw a group of trees ahead, at the curve in the road – I aimed for the largest one and accelerated’’. The patient agreed to undergo a psychiatric assessment prior to his discharge. The motor vehicle accident was assessed to have been the result of an impulsive suicide attempt, in the context of an adjustment disorder, precipitated by his marital break-up. He was also assessed to have personality vulnerabilities related to selfesteem and difficulties in coping with rejection. This was thought to be related to the reported death of his mother at an early age, which left him in the care of a violent and alcoholic father. The separation from his wife was suggested to have activated unresolved grief surrounding the loss of his mother, leading to feelings of intense despair and suicidal impulses. The patient was not found to have ongoing suicidal ideation and agreed to a followup with psychiatric services upon discharge. This case illustrates the situation whereby most trauma cases are assumed to be the result of an ‘accident’. However the doctor performing the tertiary survey became suspicious of the intentionality of the incident when the patient described favourable driving conditions and that he had been ‘‘under a lot of stress lately’’. Further exploration by the doctor allowed the patient to disclose his intent to commit suicide.
A review of the literature Motor vehicle collision is the leading cause of traumatic death worldwide1 and accounts for 45% of all hospital trauma admissions.2 The World Health Organization (WHO) estimated over 1.3 million people are killed in motor vehicle collisions each year with up to 50 million non-fatal injuries.3 The mortality rate for males is three times higher than for females and more than 50% of the mortality from motor vehicle collisions occurs in young adults (ages 15–44). The global economic cost of road traffic injuries, including medical treatment and loss of productivity, is estimated to be US$ 518 billion per annum. For each country, this typically represents between 1% and 3% of the gross national product per annum.4 Despite the availability, familiarity and lethality of motor vehicles, as well as the potential for concealing the intention, suicide by motor vehicle crash has not been recognized as a common method of suicide. World Health Organization (WHO) has estimated 0.2% of all cases of suicide are the result of motor vehicle crash.5
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A literature review on driver suicide by Routley et al. in 2003,6 examined 13 studies from different countries and found a substantial range in the reported incidence of driver suicide, with figures ranging from 1.1% to 7.4% of all motor vehicle collisions. This variance is likely due to the methodological difficulties in establishing suicide intent. Unlike other methods of suicide, such as hanging and carbon monoxide poisoning where ascertainment of intent is high, it is very difficult to establish intent of suicide in motor vehicle collisions. The studies aim to determine suicide intent by examining the physical evidence from the crash scene, such as skid marks, or lack thereof, to estimate vehicle speed or evidence of attempted collision aversion. Witnesses and relatives of the deceased are interviewed and pathology, autopsy, medical, police and coronal reports are examined in attempt to identify factors that may suggest suicide, such as recent life stressors, changes in mental state, drug or alcohol use and previous attempts or threats of suicide. The quality of the data obtained to determine intent of suicide is largely dependent on the resources of the investigating agencies of each region. The criteria used to establish a driver fatality as suicide also varied between studies. Regional religious, cultural and legal differences may also influence the completeness and accuracy of information disclosure and suicide classification. For example, the suicide rates in Roman Catholic or Moslem countries is considered to be low, however it is unclear if this reflects a true influence of religion on behaviour or is the result of systematic underreporting.7 Despite the wide variance of incidence of reported suicide, the reported rates of driver suicide have been found to be higher than official reports. A study by Ohberg et al.,8 reporting the largest number of driver fatalities (n = 1419), found 5.9% (n = 84) of driver fatalities were driver suicide. Official statistics based on the death certificates classified 2.6% (n = 37) of the fatalities as suicides, suggesting a misclassification of more than half the cases of driver suicides. Since the review by Routley et al. (2003)6, there have been six further publications relating to driver suicide. The largest and most recent study to date on driver suicide is a Finnish study by Hernetkoski et al.9 who examined 3508 fatal motor vehicle accidents during the years 1974–2006 and found 6.5% (n = 227) of cases were driver suicide. It also found the rate of driver suicide increased to 9–10% over the years 2005–2006. Bjornstig et al.10 examined 293 passenger car occupants killed in collisions with other vehicles and found 13 (4.4%) were likely to be suicides. However, this study may have underestimated the prevalence of driver suicide as the literature suggests driver suicides are more likely to be the result of single-vehicle accidents.11 A case–control study by Lam et al.12 examined the association between suicidal ideation and risk of car crash injuries. Self-reported information on suicidal ideation was collected in 571 injured motor vehicle drivers presenting to hospital and a control group of 588 uninjured drivers. The prevalence of suicidal ideation over the preceding 12 months was found to be higher in the injured driver group than the control drivers, suggesting suicidal ideation was associated with driver injury. However, this association was not present when examining drivers with a history of suicidal ideation who were taking antidepressant medication. A similarly designed study by Pompili et al.13 compared the suicide intent in 30 single-car accident drivers admitted to hospital and matched control drivers who had never had a car accident. Both groups were administered a Reason for Living (RFL) questionnaire,14 which investigated the participants attitudes to suicide. The study found single-car accident drivers scored lower on the RFL questionnaire than the driver control group, suggesting the single-car accident drivers had more ambivalence about living. Although these patients were not overtly suicidal, the author concluded ambivalence about living
A.F. Henderson, A.P. Joseph / Injury, Int. J. Care Injured 43 (2012) 18–21
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might translate into excessive risk taking, self-neglect and risk of motor vehicle injury. The WHO/EURO Multicentre Study on Parasuicide (2000) by Michel et al.5 is the largest study to date examining the frequencies of different methods of attempted suicide. The study analysed 25,816 suicide attempts across 12 European countries over a 4year period and recorded 62 cases of attempted suicide by motor vehicle crash, representing 0.2% of all cases of attempted suicides. This study suggests motor vehicle crash is the 12th most common method of attempted suicide. However, Murray et al.15 performed a random postal survey of 8677 individuals in an urban geographic region in Australia to identify individuals with a lifetime history of suicidal ideation or attempt. 412 individuals were identified to have a history of suicidal ideation, of which 14.8% (n = 61) had planned or made arrangements to suicide by crashing a motor vehicle. 228 individuals were identified to have made a suicide attempt, of which 8.3% (n = 19) were attempts by driver suicide. According to the distribution of methods of suicide in the study by Michel et al.,5 this would then place attempted suicide by motor vehicle crash as the second most common method of attempted suicide after drug and alcohol overdose. The differences in the results of these two studies could be explained by the different methodological approaches employed. The Murray et al. study surveyed the life-time history of attempted suicide by motor vehicle crash in a community sample by posting a questionnaire, which may be less confronting and may result in higher rates of disclosure of attempted driver suicide. Whereas, the WHO study relied on participants disclosing their intent of driver suicide in the course of a hospital admission for their injuries. However, the Murray et al. study has a relatively small sample size from a small geographic area thus limiting the generalisability of these results.
Risk factors for driver suicide The current literature has identified specific factors associated with driver suicide (Table 1). In 2008 the Australian Bureau of Statistics had recorded 126 cases of deliberate crashing of a motor vehicle over the previous 10 years.16 The majority were males (82.5%) in the younger age group (17.5% between 20 and 24 yearsof-age). Most driver suicides result from single vehicle crashes,11 however if another vehicle is involved, it is usually a heavy vehicle or truck10; improved modern car safety features may lead to the perception that crashing into an oncoming heavy goods vehicle is a more lethal crash target than a stationary object. Alcohol intoxication has also been implicated in driver suicide, with one study showing 79% of cases of driver suicide had used alcohol at the time of the accident.17 Depression and prior suicide attempts have also been shown to be related to driver suicide. In interviews of relatives of driver suicide victims by Hernetkoski et al.,18 48% of suicide victims suffered depression.
Discussion Road safety measures such as matching speed limits to driving conditions, greater investment in road infrastructure and campaigns against driver fatigue, drink driving and the non-wearing of seat belts have contributed to a reduction in road deaths over the last 5 years.4 However many national road safety strategies have failed to reach their target reduction in road fatality rate. Of particular concern, the road fatality rate has remained relatively static for the young/male group. One possible explanation for this is that a significant proportion of these accidents are unrecognised suicide attempts. The introduction of a nationally standardized assessment of motor vehicle crashes that cannot be readily explained, including examination of the accident site and of the victim’s psychosocial circumstances, is required to improve the ascertainment of driver suicide. Once the prevalence of driver suicide is more clearly established, the introduction of specific driver suicide prevention strategies, such as anti-collision radar (that automatically engages the brakes if an obstacle is detected) and alcohol interlock systems, may be considered to further reduce the road fatality rate. Hospital emergency department and trauma staff are in a unique position to identify cases of undisclosed attempted driver suicide. Clinical staff with an awareness of the likely frequency and familiarity with the risk factors associated the driver suicide (e.g. young, male, and single occupant vehicle) will increase the recognition and disclosure of cases of attempted driver suicide. This assessment may be formalised by its incorporation in the tertiary trauma survey.19 This assessment may consist of questions surrounding the injury circumstances, and consideration of the patient’s risk factors for driver suicide. If the patient’s replies are considered vague or inconsistent and significant risk factors are present, more direct questions regarding injury intentionality may be warranted. Conclusion Research into driver suicide is relatively sparse because of the methodological difficulties associated with establishing the intent of suicide in cases of motor vehicle crashes. Despite this, the current literature would suggest that at least 1 in 15 motor vehicle crashes are intentional and remain largely unrecognised. The literature also suggests specific crash circumstances and driver socio-demographic background factors are associated with driver suicide. Formally assessing the risk factors associated with driver suicide may increase the identification of failed driver suicide and referral to psychiatric services. This will have implications for secondary suicide prevention and ongoing medical costs. Conflict of interest statement There are no conflicts of interest in the writing and publication of this paper.
Table 1 Risk factors associated with driver suicides.
Males. Age between 25 and 34. Single occupant crash. Non-wearing of a seat belt. Head-on collision. Single vehicle crash (into a tree or pole). Collision into a heavy goods vehicle. Absence of skid marks or other evidence for loss of control over the vehicle. Alcohol intoxication/abuse. Significant recent psychosocial stress. Mental disorders (such as depression) and previous suicide attempt. Impulsivity and low distress tolerance personality trait.
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