I don't know if it was becoming "immune" to medications, but I definitely went through a period when I'd need more meds. Be OK for a bit. Need even more. OK for a bit. Need even more. Etc. I do think that there was more at play in these cases than just medication poop out, but I think medication poop out is a real thing.

There was a time when I was on a huge cocktail of 7 psychiatric meds. Luckily my psychiatrist eventually HAD to take me off some of them because of side effects. I did find that when one medication was eventually taken away, that my dose(s) of another had to be increased.

I've been on some medications that just plain didn't do enough. Lithium was never nearly as effective for me as for other people. Neither was Geodon despite being on a high dose. But Seroquel XR (at a kind of high dose) has allowed me to get down to 4 from 7. I just found the right med that packs a good punch for me. I'm hoping that my Seroquel XR dose will eventually go down so that my hunger decreases. If it does and my symptoms come back, well, I guess I'll just have to go up again.