An interesting paper on the history of suicide and the philosophy surrounding it that was usually behind a pay-to-view wall. http://plato.stanford.edu/entries/suicide/
2.1 Ancient and Classical Views of Suicide
Philosophical discourse about suicide stretches back at least to the time of Plato. Still, prior to the Stoics at least, suicide tended to get sporadic rather than systematic attention from philosophers in the ancient Mediterranean world. As John Cooper has noted (Cooper 1989, 10), neither ancient Greek nor Latin had a single word that aptly translates our ‘suicide,’ even though most of the ancient city-states criminalized self-killing.
Plato explicitly discussed suicide in two works. First, in Phaedo, Socrates expresses guarded enthusiasm for the thesis, associated with the Pythagoreans, that suicide is always wrong because it represents our releasing ourselves (i.e., our souls) from a “guard-post” (i.e., our bodies) the gods have placed us in as a form of punishment (Phaedo 61b-62c). Later, in the Laws, Plato claimed that suicide is disgraceful and its perpetrators should be buried in unmarked graves. However, Plato recognized four exceptions to this principle: (1) when one's mind is morally corrupted and one's character can therefore not be salvaged (Laws IX 854a3–5), (2) when the self-killing is done by judicial order, as in the case of Socrates, (3) when the self-killing is compelled by extreme and unavoidable personal misfortune, and (4) when the self-killing results from shame at having participated in grossly unjust actions. (Laws IX 873c-d) Suicide under these circumstances can be excused, but, according to Plato, it is otherwise an act of cowardice or laziness undertaken by individuals too delicate to manage life's vicissitudes. Aristotle's only discussion of suicide (Nicomachean Ethics 1138a5–14) is a difficult and confusing passage in which he attempts to explain how suicide can be unjust and deserving of punishment if the individual who could be treated unjustly is the suicidal individual herself. He concludes that suicide is somehow a wrong to the state