It seems to be widely reported that those who regulaly consume plenty of alcohol develop a tolerance to it - so it takes an increasing quantity to produce the same intoxicating effect.
My question: what is the metabolic mechanism that accounts for this? Something to do with the liver’s ability to process alcohol? Something in the brain?
To expand the question into the general case, the answer is, “both”. From Drug tolerance - Wikipedia : “Drug tolerance can involve both psychological drug tolerance and physiological factors.” That sentence has live links. Check them out, they’re pretty interesting reading.
The enzymes that process alcohol in the liver, a subset of the CYP 450 family, can be induced, meaning that the process to make more of them is kicked on by the presence of the stuff they process. If somebody drinks a lot, their livers start making more of the relevant enzymes, which lets them break down the alcohol faster, increasing their tolerance. It’s also somewhat genetic - some people are born with a predisposition to make more CYP 450 than others.