Self poisoning with pesticides

Self inflicted violence

Self harm is a major problem in many nations in the Asia Pacific region, from the Pacific islands of Fiji and Samoa, to Asian nations as different as China and Sri Lanka.3 Suicide accounted for 71% (512 000/722 000) of all violent deaths in South East Asia and the Western Pacific region in 2000.2 Most deaths occur in rural communities: the incidence of fatal self harm in rural China is three to five times that in urban China,4 and self poisoning is the commonest cause of inpatient death in some rural Sri Lankan districts but a rare cause in the capital city.5

Suicide or fatal self harm?

Some experts believe that a distinction exists, particularly in terms of intent, between people who harm themselves (attempt suicide) and those who die (commit suicide).6 WHO's report on violence and health, however, acknowledges that, although an intent to die is a key element of suicide, determining the level of intent for an individual is difficult.2

Toxic pesticides are readily accessible in farming households of the developing world

Self harm, in particular self poisoning, is used for many reasons—to gain attention, express distress, or get revenge—not just for ending life.7 8 We think that many deaths from self poisoning in Asia Pacific occur in people who do not intend to die; they die because the poisons ingested are very toxic and patients are difficult to treat.3 9

Role of mental illness

WHO's report supports the common view that fatal self harm is always associated with a mental disorder.2 It does not consider the issue of impulsive suicides in people without mental illness. A meta-analysis by Bertolote and Fleishmann reported that 98% of fatal deaths from self harm occur in people with definite mental illness.10 But studies from China, India, and Malaysia suggest that a substantial proportion of people who die from self harm do not have a diagnosable mental illness.9 11^–13

Self poisoning often occurs immediately after an acute relationship crisis not after long hours of premeditation.7 9 In one study of 326 people who had carried out serious but non-fatal acts of self harm in China,14 83% had ingested pesticides, only 40% had a diagnosable mental illness, and 35% reported that they first considered harming themselves 10 minutes or less before making the attempt.

Comparison with Britain

Self harm, in particular self poisoning, is common in the United Kingdom. However, most of the 3000-4000 deaths that occur each year from self harm are the result of gassing or physical acts such as hanging, not poisoning (figure).15 16 A high proportion of people who carry out such acts die, usually outside hospital. The premeditation required for these methods of self harm suggests that intent to die is high.

Comparison of methods used for fatal self harm in England and Wales, Australia, and Asia. Data for England and Wales (n=3480)^w1 and Australia (n=2683)^w2 are national, presenting only confirmed suicides; Data for Jaffna, Sri Lanka, (n=612) are from a review of coroner's records;^w3 and for China; (n=519) from a national study9

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British hospitals deal with over 100 000 cases of self poisoning with medicines each year.16 Intent to die among people who self poison, unlike those who gas or hang themselves, is generally low and the case fatality very low: fewer than one in 300 people (0.3%) who reach hospital die. The poisons are not particularly toxic, effective antidotes are widely available, and medical management is simple. In 2000, only 712 people died from intentional self poisoning in Britain.^w1

By contrast the case fatality for self poisoning in rural Asia is 10-20%.3 As a result, most deaths from self harm are due to poisoning and not physical acts (figure). A study from China that examined a nationally representative sample of 519 suicides found that 62% of deaths were due to pesticide ingestion and only 27% to physical methods.9 Moreover, 89% of the pesticide deaths occurred in rural farming households.9 Thus, in China alone, an estimated 175 000 (62% of 287 0004) deaths occur each year from pesticides, most in farming communities. Tens of thousands more rural deaths from self poisoning with pesticides occur in other Asia Pacific countries.

Since 1960, the Sri Lankan suicide rate has increased by over 700%.^w4 This has been almost entirely due to an increase in the incidence of fatal self poisoning with pesticides because the incidence of all other methods (except plant poisoning) has remained stable.^{w4 w5} This rise in suicide rate has been much studied; suggested reasons include the civil war and frustration felt by educated young people because of lack of opportunity.^w4 A simpler reason may be the introduction of pesticides into everyday use during the green revolution.

Medical management of pesticide poisoning

In our ongoing study of self poisoning with pesticides in Sri Lanka, 12% of patients required intubation (unpublished data). Half of the patients died and entered the suicide statistics. Many of the survivors would also have died if there had been no endotracheal tubes, laryngoscope, or doctor capable of intubating them. Such situations are common across the developing world. Patients die from aspiration or respiratory failure because doctors in small rural hospitals do not have the equipment or skills to intubate or the ventilators to support heavily sedated patients.

Essential antidotes are often lacking: atropine has been unavailable in parts of Nepal for many months (L Karalliedde, personal communication). It is impossible to manage serious organophosphate pesticide poisoning without atropine. A similar situation currently exists with yellow oleander poisoning in Sri Lanka: the lack of an affordable antitoxin means that patients must be transferred across the island to access pacing facilities.17 Many die during transfer.

Thus, the factor determining whether self poisoning is fatal or not is often medical, and nothing to do with the attempt itself (box). A parallel situation could occur in Britain if, for example, no antidote was available for paracetamol poisoning. The resulting higher case fatality for this common method of self harm would produce a substantial rise in overall suicide rate without a change in the degree of intent to die.

Recommendations for reducing deaths from self harm

WHO's report makes several recommendations to reduce the incidence of suicide—for example, improving recognition and management of mental disorders and strengthening community based support systems.2 Although these are important strategies for reducing fatal self harm globally, their ability to reduce deaths in rural Asia is questionable.

The report also suggests restricting the availability of methods for self harm (such as fencing in high bridges and restricting access to dangerous medicines or pesticides). This approach could have a rapid effect, but the report qualifies that access to pesticides should be controlled for only people “other than farmers.”2 Since over 80% of households in the developing world farm some land, most people in rural Asia would not be affected by the recommended restrictions. Indeed, most fatal pesticide ingestions occur in farming households.9

Primary and secondary prevention strategies relevant to the rural developing world are possible. However, pesticide regulation has to be nationwide and must apply to everyone, particularly farming households. It could include deregistering highly toxic pesticides or only allowing the use of the safer pesticide when two pesticides do the same job.18 Other methods might be to give legal authority to use pesticides to just a few people in each community (thus taking pesticides out of most households) or to provide lockers for storing pesticides away from houses so that they are not close at hand during moments of stress.

Improved medical management of self poisoning could also reduce suicide rates rapidly3 ^w6 since most patients with pesticide poisoning reach hospital alive.9 ^w7 Improvement will come from clinical research, implementation of findings into clinical practice, and improved supply of essential antidotes.

Halving the case fatality of pesticide poisoning in Sri Lanka from 20% to 10% would reduce the annual number of inpatient pesticide deaths by about a 1000. The national number of suicides would consequently fall from 4500 to 3500, a 22% reduction. Our ongoing study of the management of pesticide poisoning indicates that such a reduction is possible by using standardised protocols and good supportive care (unpublished data).

A similar reduction could be expected in China, where 59% of people who die after self poisoning receive medical treatment before dying.9 This represents 36.6% of all Chinese suicides, or 105 000 suicides annually. Thus halving the case fatality among people who receive treatment after ingesting pesticides would save over 50 000 lives a year and result in an 18% drop in the overall suicide rate.

Conclusion

Strategies to reduce the prevalence of mental illness and to increase the level of psychological and social support in rural communities should reduce the incidence of fatal self harm. However, such approaches will take time. We believe that national pesticide regulation and improved medical management will have a rapid effect possibly producing 100 000 fewer deaths a year in the Asia Pacific region alone. We hope that WHO will incorporate these approaches into its strategy to deal with this major global public health problem.

References w1-w7 are on bmj.com