sanmac - // Agchristie, my sister committed suicide, and obviously I knew her very well. But I, and the rest of the family, still don't know why she did it. //
I don't wish to de-rail the thread, but your post did prompt a response from me.
I was a Samaritan volunteer for three years, which taught me about suicide from an intellectual perspective, and I was a psychiatric patient for three months, and remain on medication thirty years later, which has taught, and continues to teach me, about suicide from a personal perspective.
That combined experience leads me to the unshakable conclusion that I believe that every single suicide takes their life for exactly the same reason - you just have to be desperate enough for death to be a welcome attractive viable alternative to living for the next sixty seconds.
That may help you, I don't know, but I have put it out on this site many many times over the years, and the older I get, the less chance there is of me ever altering that view, seriously hard won as it has been.