You got addicted to Tylenol? Could you be more specific? Do you just mean that it stopped working for you? Because if you mean you truly developed a compulsive desire to take APAP, you must be the first person in the world ever to have done so.

It is possible to be addicted to anything and it is quite easy with any painkillers, it doesn't have to opioid based one. Subconscious fear of pain is enough to take them in advance, just in case, every day.

No no, not in advance, but when I could claw my eyes out because of the pain - the problem was that slowly, year after year it worked less and less.

APAP metabolizes to AM404 in vivo, which acts indirectly on the cannabinoid receptor type 1. AM404 is likely responsible for a large amount of the pain relief (and, unsurprisingly, an anticonvulsant effect).

I suspect it's tolerance and not addiction, but docs see this and code it as "medication overuse headache" all the time.

Saridon but all the same I guess. Not my wording though, but the doctor's.