There are inevitable physical changes that occur as we age, nearly all of which also affect brain chemistry to some degree. Other physical events (in my case, breaking a bone in my late sixties) also brought a major physical change: I already suffered from moderate arthritis, but the break increased the inflammation--especially at the Sita of the break.
My bipolar disorder was intricately connected with all of these changes, and my pdoc worked with me and the rest of my medical team to make sure we were in tandem with adjustments.

The physical and mental activity is so important, emomom, along with the right meds ... and it all becomes a multidimensional puzzle as we age. I've found, for me, that rest and detox is also important.

Best wishes.
Roadie