I feel like this has happened with my grandmother. She’s in her 90s and mostly still there, but she has outlived my grandfather and most of their friends. She’s also quite feeble and didn’t leave the house, and broke her hip this year (and miraculously made it through a very risky surgery). Family members in the area visit her often and she has a live in care taker, but the last few years she’s started to have minor delusions. Mostly, she’ll talk about seeing “little people” in the yard. If you have a conversation with her, she’s as present as most people that age I’ve interacted with.

I suspect she basically has low-grade cabin fever. The delusions only started shortly after her husband passed and she was alone. Even putting aside the concerns about the elderly driving, my grandfather insisted on driving everywhere so she essentially couldn’t drive to see people. She hasn’t been strong enough to really cook or clean outside of very simple tasks in a while. Her only real stimulation is / was when we visit.

I was going crazy when quarantining with Covid for 7 days, and I felt any mild social interaction taxing afterward for another week or so because that muscle was atrophied (I’m not particularly introverted or shy). I can’t imagine being confined to one room of a house hoping someone visits me for an hour each day as my only source of interaction with the world.

On the flip side, I did some work for an emeritus professor when I was in undergrad. The guy was 89, came in 4 days a week to work on his (successful) hobby project invention, was sharp as a tack, and could solder SMD components with steadier hands than me. The only reason he even needed my help was he never learned to code (he was well into tenure by the time programming a PC became necessary for his research so grad students handled that and then hired undergrads when he stopped running a lab).

Both examples are anecdotal evidence, and maybe I’ll have a different opinion when I’m older, but the traditional full retirement if you are otherwise healthy seems like a good way to waste away. I think having some responsibilities keeps you connected, energized, and motivated to keep living.