After thinking on it some,
I suppose older individuals 'could be at higher rates of depression,
And then when people get depressed they sometimes stop doing stuff, stop doing stuff that relieves depression, viscous cycle.
But sometimes one's friends or family are dying, some are divorced or alone, maybe they've retired or 'can't keep working, and working 'was their main go to, they never developed other hobbies.
Physical limitations, aches and pains, medical issues pop up sometimes, maybe there's worries about making a living or their futures.
Course, higher risk doesn't mean certain outcome.
People can depressed at all stages of life I'm sure.
Teens, school or family pressure, social confusion, body confusion and hormones, developing world views.
Mid life people, Mid Life Crisis, job, family, money.
Eh, if you're worried about old age, just consider the possible dangers, then safeguard against them as best you can. Develop the vision to see ruts, then avoid them.
. . . Just don't hyperfocus on it, that's how one could get Hypochondria, I imagine.