From pesticides to medicinal drugs: time series analyses of methods of self-harm in Sri Lanka

Abstract

Objective: To explore if recent changes in methods of self-harm in Sri Lanka could explain the decline in the incidence of suicide. Methods: Time series analyses of suicide rates and hospitalization due to different types of poisoning were carried out. Findings: Between 1996 and 2008 the annual incidence of hospital admission resulting from poisoning by medicinal or biological substances increased exponentially, from 48.2 to 115.4 admissions per 100,000 population. Over the same period, annual admissions resulting from poisoning with pesticides decreased from 105.1 to 88.9 per 100,000. The annual incidence of suicide decreased exponentially, from a peak of 47.0 per 100,000 in 1995 to 19.6 per 100,000 in 2009. Poisoning accounted for 37.4 suicides per 100,000 population in 1995 but only 11.2 suicides per 100,000 in 2009. The case fatality rate for pesticide poisoning decreased linearly, from 11.0 deaths per 100 cases admitted to hospital in 1997 to 5.1 per 100 in 2008. Conclusion: Since the mid 1990s, a trend away from the misuse of pesticides (despite no reduction in pesticide availability) and towards increased use of medicinal and other substances has been seen in Sri Lanka among those seeking self-harm. These trends and a reduction in mortality among those suffering pesticide poisoning have resulted in an overall reduction in the national incidence of accomplished suicide.