By "brain dead", I meant that I had difficulty focusing, and felt somewhat sedated. But then, I take so many drugs now that it's hard to really know which are doing what.

I mean, I could have increased the modafinil dose. But it was easy enough to take hydroxychloroquin at night, and naproxen in the morning. And hopefully my kidneys will be happier, even if my retinas etc are more at risk.

Methotrexate (Sarcoidosis) here, not hydroxychloroquine, both are DMARDs.

"Brain fog" is a more commonly used term, although no doubt people experience different things and would describe them differently. For me, it's a weird feeling of vagueness, and to what extent varies significantly. Sometimes it's hard to focus and do work, but not always. Usually it's just like everything is sort of "passing me by". You wouldn't know talking to me, I function just fine, so maybe it mostly just affects my perception of time and/or memories. It's subtle and weird.

interesting. do they know why it's happening ?

I'm actually not sure, but it's one of the most common side effects. These are pretty intense drugs. Methotrexate quite literally stops cell division; in much higher doses than I take, it's used to abort nonviable pregnancies.

EDIT: I should probably note that stopping cell division isn't the primary mechanism by which Methotrexate treats Sarcoidosis. You basically take Methotrexate then 24+ hours later counteract it with folic acid. They actually don't know how it works!

In my case it probably doesn't help that "brain fog" is also a side effect of Sarcoidosis itself; I mean that's obviously pretty minor in comparison to the fact if left unchecked it'd destroy my lungs.