Suicide

Suicide is recognised in all human populations, but at widely differing rates. Durkheim who was the first to undertake systematic studies maintained that suicide rates were a function of anomie or lack of coherence in society. More specifically rates are generally increased in those who are mentally ill, particularly with the psychoses (schizophrenia, schizoaffective illness and manic-depressive disorder) and are generally estimated as having a 10% lifetime risk by comparison with approximately 1% in the general population. Rates are also increased in physical disease, particularly when chronic and progressive.
 
Interestingly evidence from adoption studies suggests a genetic component in predisposition to suicide that is independent of psychiatric illness.
 
A reduction in suicide rates can be achieved for example by reducing the carbon monoxide content of coal gas, or the availability of certain analgesics.
 
Most studies show an increase in suicide with age, and an excess in males, but there are exceptions. Some national differences have been related to religion, rates in Catholic countries being generally lower, but such estimates are affected by tendencies to avoid legal registration of a death as a suicide.
 
Suicide is generally distinguished from attempted suicide or self injury, the age range and sex ratio of the latter being younger and less biased to males respectively.
 
The dependence of suicide rates on social factors is dramatically illustrated by the phenomena of kamikaze pilots and suicide bombers. the mass suicide of the Jones cult in British Guiana is also salutary.