The WHO and the International Association for Suicide Prevention are holding their second annual World Suicide Prevention Day today.
Almost a million people take their own lives each year and the number, which exceeds the death toll from murder and war, is expected to hit 1.5 million by 2020.
More men than women take their own lives, but a greater number of women than men attempt suicide.
The highest suicide rates are found in Eastern Europe - notably in Lithuania, Estonia, Russia, Latvia and Hungary - and the lowest in Latin America, Muslim countries and a number of Asian states. There is little reliable information on rates in Africa.
The main suicide triggers are poverty, unemployment, the loss of a loved one, arguments and legal or work-related problems, but alcohol abuse can increase the impact of such problems in individual cases.
There has recently been a significant increase in suicidal behaviour among young people aged 15 to 25 years. Experts say this may be related to a generally greater availability of handguns.