Some suicides - what we might think of as "heroic suicides" or "altruistic suicides" - are committed for the benefit of others, perhaps to save others from death. Often, these are not even seen as belonging to the same class as regular suicides.
When considering altruistic suicides, does it matter whether the harm (perhaps death) the suicide saves others from would come from outside circumstances, or the suicide's own future actions if he were to stay alive?
Generally, people recognize the value of not harming others. Sociopathic personality disorder may be associated with many types of harm to others, but it seems reasonable to acknowledge that there are many people who, despite understanding that it is wrong to harm others, nevertheless go on doing so out of weakness of will. Some people cannot help themselves, in a practical sense, from doing serious wrong (as may be the case with some rapists). They know it is wrong and feel empathy for their victims, but go on harming people anyway. And some of these people, we might assume, have insight into their akratic condition - not only do they know that it is wrong to harm others, but they realize that they are likely to do it, no matter how much effort they expend to avoid doing so. I propose that when a person such as this commits suicide for the purpose of preventing his future harm to others, his suicide is altruistic. Note that this doesn't cover cases where, for example, convicted child molesters commit suicide upon release because of difficult living conditions, or even out of guilt for prior crimes. Many suicides might have the unintended consequence of avoiding harm to others, but I would only classify those as altruistic that have the purpose of preventing harm to others.
I mention this to show that the category of "altruistic suicides" might be broader than it appears.