Professor David Gunnell of the University’s Department of Social Medicine and colleagues from the South Asian Clinical Toxicology Research Collaboration in Sri Lanka found that Sri Lanka’s import restrictions on the most toxic pesticides were followed by marked reductions in suicide.

Between 1950 and 1995 suicide rates in Sri Lanka increased 8-fold to a peak of 47 per 100,000 in 1995.  By 2005, rates had halved.  The researchers investigated whether restrictions on the import and sales of the most highly toxic pesticides in 1995 and 1998 coincided with these reductions in suicide.

They found that 19,800 fewer suicides occurred in 1996-2005 compared with 1986-95.  Other factors that affect suicide rates such as unemployment, alcohol misuse, divorce and war did not appear to be associated with these declines.

Pesticide self-poisoning is thought to account for an estimated 300,000 deaths in Asia – over a third of the world’s suicides. 

Professor Gunnell said: “Changes in the availability of a commonly used method of suicide may influence not only method-specific but also overall suicide rates.

“Pesticides are readily available in most rural households in low income countries and are commonly used by young people who impulsively poison themselves in moments of crisis. 

“Our research suggests that restricting the availability of toxic pesticides should be prioritised.  We propose that other countries such as China and India where pesticide self-poisoning is a major health problem follow Sri Lanka’s example in comprehensively regulating pesticide imports and sales.”