On this site, there is a menu at the top where you can click on "Reasons for Suicide". There's a list, and then there are sections with very interesting information.

http://en.wikipedia.org/wiki/Suicide


Views on suicide have been influenced by cultural views on existential themes such as religion, honor, and the meaning of life. Most Western and some Asian religions—the Abrahamic religions, Hinduism—consider suicide a dishonorable act; in the West it was regarded as a serious crime and offense against God due to religious belief in the sanctity of life. Japanese views on honor and religion led to seppuku, one of the most painful methods of suicide, to be respected as a means to atone for mistakes or failure or a form of protest during the samurai era. In the 20th century, suicide in the form of self-immolation has been used as a form of protest, and in the form of kamikaze and suicide bombing as a military or terrorist tactic. Sati was a Hindu funeral practice in which the widow would immolate herself on her husband’s funeral pyre.[4]

Medically assisted suicide (euthanasia, or the right to die) is a controversial ethical issue involving people who are terminally ill, in extreme pain, and/or have minimal quality of life through injury or illness. Self-sacrifice for others is not usually considered suicide, as the goal is not to kill oneself but to save another.