Violent suicide and obstetric complications

Each year in England and Wales there are 5500 suicides and deaths from undetermined external cause (these are mostly suicides leading to an open verdict at inquest), and almost half are by methods involving physical injury.¹ These methods are diverse and include hanging, jumping from a height or in front of a moving vehicle, burning, and firearms. They do, however, have common characteristics which allow comparison with suicides by non-violent methods such as poisoning by overdose or car exhaust fumes. Both violent methods and asphyxiation by exhaust fumes are substantially more common in men (as are other types of violent behaviour), in whom hanging is now the most common method of self destruction.¹ Violent suicides are associated with severe mental illness such as schizophrenia and major affective disorder,² although mental disorder of some kind is found in most suicides.³ Internationally the method of suicide is also influenced by local factors including availability, so that jumping from buildings is particularly common in Hong Kong⁴ and deaths from firearms are related to gun ownership in the United States.⁵ Nevertheless, the links between violent suicide and both male sex and mental illness generally hold true.

Researchers from Sweden describe in this issue how they have tried to trace the origin of violent suicide to perinatal experience (p 1346).⁶ Jacobson and Bygdeman obtained birth records for a sample of individuals who had committed suicide by violent means in 1978-95 and who had been born in one of seven Stockholm hospitals after 1945. The records provided information, extracted by blind raters, on obstetric complications, including atypical presentation, meconium staining of the amniotic fluid, assisted delivery, and neonatal resuscitation; the total number of such incidents was recorded as an individual’s “trauma score.” The number of doses of opiates administered in the 24 hours before delivery was also recorded.

The people who committed suicide were then compared on these variables with their siblings who had been born in the same hospitals but who had not committed suicide (suicide victims without siblings were excluded from the main analyses). Using siblings as a comparison group allowed cases and controls to be matched on some potentially confounding social and family variables. The authors also report that suicides and their siblings had a negligible average difference in year of birth, though this is not the same as eliminating the confounding effect of year of birth: both suicide rates and obstetric practice have significantly changed over time.

The study found that people who committed violent suicide had higher rates of some obstetric complications, higher trauma scores, and lower rates of opiate administration. In a multivariate analysis violent suicide was predicted by maternal age, male sex, absence of opiate administration, and an interaction of male sex and trauma score. The findings extend those of a United States study which found perinatal complications to have been more common in adolescents who committed suicide.⁷

It is not, however, the findings of the study but the authors’ interpretation of them that will attract most attention. Jacobson and Bygdeman conclude that the pain experienced by infants during complicated delivery is likely to be linked causally to violent suicide. The findings are presented as supporting their hypothesis that when committing suicide some people unconsciously recreate the traumatic sensation of their birth. They believe the causal mechanism to be imprinting and point to the specificity of the effect on males as supportive evidence, because testosterone is known to enhance imprinting in animal studies. They argue that to avoid future increases in the incidence of violent suicide obstetric procedures should aim to prevent infants from experiencing “even slight physical discomfort.”

Here they can expect to part company from most suicide researchers. Those who accept the imprinting theory will need to be confident that they have the answer to a number of questions. To what extent are the obstetric complications in the study, and the trauma scores derived from them, a valid indicator of infant pain? How strong is the evidence that infant brains store perinatal experiences, let alone recreate them in adulthood? In what sense does hanging or jumping off a building correspond to forceps delivery or neonatal resuscitation?

Any link between obstetric care and violent suicide is more likely to occur through mental illness. Considerable evidence exists that obstetric complications are associated with schizophrenia. A recent meta-analysis, finding the association to be strongest in early onset cases, concluded that neurodevelopmental impairment, possibly the result of fetal hypoxia, was part of the causal process in these cases.⁸ A similar neurodevelopmental hypothesis has also been proposed for major affective disorder.⁹ Any factor associated with severe mental illness is likely to be associated also with violent suicide.

However, even an indirect link between perinatal trauma and suicide may be important, although the potential to reduce the numbers of violent suicides through improved obstetric care is then far less than the attributable risks calculated by Jacobson and Bygdeman would suggest. Their study reminds us that the road to self destruction is long, but the key issues for suicide prevention remain: to understand and reverse the doubling of suicide rates in young men over the past two decades; to develop services that will reduce risk after deliberate self harm; and to find the evidence on interventions that will make mental health care safer.

Papers p 1346