DISCLAIMER: This is just an anecdote - not supposed to detract from the thread - just interested
Pat, so what you are saying is, it's to do with loss of ability to participate in activities they have loved during their lifetime? E.g. physical capabilities to do so, people to do these things with, etc?
Anecdotally, I have just been doing some research with people who have a huge passion with the marine environment. I won't go into details but while these thoughts are not really relevant to the project per se, some of the older men in the sample talked a lot about the day that they will not be able to go boating and yachting etc.
They are getting there now ... and the language that came out was all around depression ... loss of passion and lust and love for life ... because they have lost something that has been such a huge part of their lives for so long. It is as if long as they are able to sail ... or even just keep their vessel, even if they're not actively using it ... they are still active and ALIVE.
Once they lose it, it's symbolic of the beginning of the end of their lifetime. Breaking their connection with their passion is like breaking their connection with the living world because it is so painful to lose. The words they used to describe it just evoked a depressed mindset - it was sad to watch ...
I know there are many things around health, etc, that also plunge older people in depression (losing friends, partners, health issues) but I suppose I just found this aspect interesting - the symbolism of a loved activity being curtailed pretty much meaning 'this is the end of my life'.
Just off topic ramblings - sorry.