In 1969, my older brother attempted suicide at the age of 5. He created a noose and hung himself in the garage because he thought my father, who was overseas in the Navy, must have died and quote, "wanted to go to heaven and visit him."
Fortunately, someone found him before he died. His face was already blue, however, so he wouldn't have lived much longer.
Doctors at the time struggled with the same question and, as I understand it, presented my brother's case in a medical conference.
My father immediately retired from the Navy and our family took a break from going to church for a while. My brother went into therapy (such as it was in those days) and is a successful, professional adult with a family.
Over the years, we have discovered that suicides actually run in our family! (It used to be such a dirty secret, no one talked about it!)