Very very recents studies show that women don't exhibit that same heart attack symptoms as men. This could very well be one of the reasons that they are hale and hearty one moment and dead the next.

As for kissing clay cold lips -- I suppose that viruses and bacteria could easily be spread that way.

But I have experienced at least two cases in my own family where the will to live simply became non-existent and the people (one elderly, one in his 30s) can only be said to have wished themselves to die and did.