Smart.
Consider those individuals you believe to be the most intelligent people to have lived: Socrates, Einstein, Hawking - whomever. They have existed, and continue to exist, people of far greater intellect than these figures whom we idolise as the most capable minds. Individuals capable of fathoming answers to the most complex philosophical problems; who, given the chance, could solve all issues of import to humankind easily.
Of course, you may wonder why you have never heard of such a person, why they haven't received accolades and exposure for such abilities. The answer is this: they all perish at a young age, before there is any chance for them to be recognised and established as the possessors of such intellect. What fate, you might ask, befalls these prodigious people, who have the strength of mind to contemplate the meaning of life itself? It is the same for every one of them: suicide.