Morticia, You said "I seem to be prey to whatever mad notion springs into my head." A Bhuddist teacher I knew once said that it's OK for you to let any thoughts whatsoever come into your mind, since they're going to come into your mind no matter what you do, but you don't have to let them set up a tent & camp out in your head. So just welcome them all in, & ask the ones you don't like, that don't serve any purpose, to leave... They're just passing through...

I used to wonder why people took their lives, instead of a boat to Tahiti or something. Then I experienced chronic depression & realized that if I went to Tahiti, my depression would come with me. Fortunately there are so many ways to cure / deal with medical, psychological, social, financial, etc. problems, these days that almost everyone can find some people & things that will help them. But I have read about celebrities who've had all the financial & social resources, they tried everything, their loved ones supported them, but modern medicine just didn't have anything to help them. I don't know what David's circumstances were, but I know it helps me alot when someone else is / was suffering, to know that everyone is doing / did the best they could, but life happens & we can't do any more than we can...