Ginny...
This isn't very scientific, but I am 62 and bi-polar most of my adult life. In the past two years I have definitely seen a change in course in my bipolar episodes, tending more towards the depressed side and I had one bout of depression that lasted 8 months. I have more agitated depression episodes. The manic portion is pretty much under ontrol. My doctor says I have early dementia. My father who was bpolar definitely had more issues with depression as he aged and he died of Alzheimers. My personal opinion is all the meds we take catches up with us as we age and manifests it in memory loss type diseases.