Prednisone can cause depression for some people. That is how it effects me. I won’t take it for that reason. It’s hard enough to have to struggle with PMR. I can’t imagine clinical depression and PMR together:(:(:(

Betsy, how are your other labs? The reason I ask is because at the beginning of the year I had an episode of depression and fatigue that I couldn't account for. Felt very organic. My white count was up above normal and my monocytes were up. Primary doc suspected a virus (but not Covid). I just took care of myself the best I could, lots of D amd C , stuff for my immune system, I'm sure you know the drill. Interestingly, I was tapering on my pred at the time and then I flared (after the "virus") and had to go back up. My white count (and my mood) are back to normal now but stil at 12 mg of pred so doesn't seem related. But the depression is alful, I know. See your regular doc and see what else could be happening. You will be in our thoughts.

I Betsy @betsy1958, I would like to add my welcome along with @kimmur, @suetex and others. You will notice that we moved your post to an existing discussion on the same topic. I'm sorry to hear that you are having depression side effect of prednisone along with the PMR. You mentioned that you are down to 5mg prednisone now in your 2 year journey with PMR. My first round with PMR lasted 3-1/2 years but I made some lifestyle and eating changes the second time around and it helped me taper off of prednisone in about 1-1/2 year. I agree with @suetex that it might be a good idea to discuss your symptoms and possibilities with your doctor or rheumatologist.

Has the depression just recently started or has it been for the entire 2 years while on prednisone?

I'd suspect it may have to do with your adrenals being slow to wake up after relying on the prednisone for several years. I've read many reports (on the HealthUnlocked PMR site out of the UK) about the symptoms people have when they get down to the dosage you are on...depression, exhaustion, mood swings. If that's what it is, you just have to tough it out until your adrenals are fully functioning. The good news is that it's temporary (but it may last longer than you'd like) and that you're only on 5 mgs.

As a p.s. to my message below, here are some links you might find helpful. You can start with "Member experiences"
https://healthunlocked.com/pmrgcauk/posts/private/147367877/adrenal-glands