The question I want to address is when and why suicide is morally wrong. There is something peculiar in my writing on this question at all. It will soon become apparent that although I think suicide involves genuine moral issues. I also think that the moral problem of suicide is a problem which most people answer correctly. That is, I think that in the vast majority of cases where people ought not to commit suicide, they do not. They are not even tempted. Conversely, most people who do commit suicide, or who want to, are either justified or at least have very substantial excuses for their behavior or desires. I am not moved to write about suicide, and to argue that it is normally wrong, by the belief that wrongful suicide is a pressing practical problem or by the belief that we need to do more to discourage or prevent suicide. Whether suicide is a pressing problem and whether we should do more to prevent it are issues that are irrelevant to my present concerns.
Regan, Donald H. "Suicide and the Failure of Modern Moral Theory." Suicide & Life-Threatening Behav. 13, no. 4 (1983): 276-92.
Available on the publisher's website at: http://onlinelibrary.wiley.com/doi/10.1111/j.1943-278X.1983.tb00024.x/pdf