How did "pissed" come to mean "drunk" or "angry"?

From the etymology of piss (v.): etymonline

late 13c., from Old French pissier "urinate" (12c.), from Vulgar Latin *pissiare, of imitative origin.

indeed reveals its literal association to urine. As @johnlowler noted in a comment on the variation in AmE and BrE, but I can find no facts as to the "what is the relation" (the when is easy). There are many phrases and phrasal verbs using piss, most dating to the middle ages.

To answer the angry part of this. I believe some say that the phrase originates from "Pissing Blood", which is where someone gets so angry that they rupture a blood vessel which causes them to urinate.

It was the early 19th Century when the word came to mean drunk, but it is unclear why. I suspect it was just used by an author in a book or play and became a popular turn of phrase. (Charles Dickens and William Shakepear were both well known for making up many words and phrases which took off and are still used today.)

The application of piss or pissed to anger was first documented as an expression just after World War II. In two articles from American Speech in the same year, Fred Eikel, Jr. and Joseph W. Bishop, Jr. each documented the usage.

Here is Eikel, Fred. “An Aggie Vocabulary of Slang.” American Speech, vol. 21, no. 1, 1946, pp. 29–36. JSTOR, www.jstor.org/stable/487347, p. 33.

HE PISSED (or PEED) ME OFF. An expression used of a person who in any way disappointed the speaker.

This usage comes from Texas A&M, which at the time had a major military presence.

Here is Bishop, Joseph W. “American Army Speech in the European Theater.” American Speech, vol. 21, no. 4, 1946, pp. 241–252. JSTOR, www.jstor.org/stable/487320. p.249.

a. Pissed-off (or P'd off). This means, roughly, fed-up, irritated, depressed. I have no idea of its history. The British say browned off and it may be that the Americans who borrowed the phrase simply felt that 'browned' was not strong enough. The superlative is, for some reason, highly pissed off, which may also be a Briticism.

Bishop is an amateur recording slang from his time in service. His note - "I have no idea of its history" - carries over to explaining why this usage appeared, or what its precise relation to micturation is. The guess of an association with "brown off" is possible, as is an attraction to the vulgarity of "piss" or an affinity for another figurative usage of "piss."

In some Indo-European language that I forgot to note, urine has a root etymologically close to the meaning "sour". Thus compare for analogy German sauer ("sour"), stinkig ("stinky")--both figurative for anger. An analogy might be visible in the theory of humors, if a bad liver causes urine to stink--cf. choleric.

Caveats: I have trouble remembering the word I'm alluding to (Armenian probably). A notion of similarity between PIE roots does not satisfy the linguistic scholarship ^[1]. Implying that pissed ~ pissy came through analogy to a word meaning stinky or sour only shifts the problem from one figurative meaning to another.

The drunk sense might be a) derivative in the sense wild, furious, b) from the above analogy to "stinky" c) derivative of pissed-off, "gone" in a sense "absent minded, unconscious", d) literal, e) something else.

Slurls involving piss are numerous (e.g. Greek "adulterer") and to a degree obvious or superficial enough not to need an in-depth etymology (unlike Greek "adulterer"). If there's more than sound symbolism to the word-stem, though, then involved idioms might help to figure out the root; Conversely, if it's really just sound immitative, then it's probably not very relevant to the question.

_{1: Compare e.g. "*súHros (“sour”)" and "Proto-Indo-European *seHur 'to piss, make water'."}

The much more attractive angle should be "drunk", if it can be related to any of the various Proto-Indo-European roots for drinking and water (thus e.g. "Lower Sorbian: piś", see *peh3-, etc.). Compare als buzz.

Sorry to bump an old post, but in Europe the use of fly agaric mushrooms predates alcohol by thousands of years. Magic mushrooms was the recreational drug of choice until the invention of vodka for many people on the mainland.

Mushrooms also contained many harmful chemicals, but the psychoactive chemical muscimol could pass through the body mostly untouched. Reindeer herders used to collect vast quantities of reindeer urine in order to safely imbibe the hallucinogenic drug, and the chemical could pass through six people before it lost its potency, so people would take the mushrooms (either dried or from reindeer urine, as the reindeer seemed to enjoy eating it and felt no ill effects, but obviously not all people had access to reindeer) and collect the urine and then have another go, or pass it around.

It seems like this is the historic origin of 'getting pissed' and probably 'going out on the piss' the word itself just carried over to alcohol when drinking became the norm.

No doubt beer being the same colour as piss, and making you urinate more frequently is the reason the ancient term stuck.

As for a few more, though you haven't specifically mentioned them, the phrases 'piss poor' and not having a 'pot to piss in' come from medieval tannerys. It took a lot of urine to tan animal skins, so if you didn't have any money three family would all piss in a pot and take it to the tanner to sell in order to eat, thus being 'piss poor' but the even more impoverished and unfortunate literally didn't have 'a pot to piss in'

Piss, as alcoholic drink, is first attested in 1925 but almost certainly was used in spoken English before that:

3. Alcoholic drink; esp. drink which is regarded as weak or unpalatable alcohol. Cf. on the piss at Phrases 3 and gnat's piss n. at gnat n.1 Compounds, panther piss n.

Sometimes (esp. in Australian and New Zealand use): spec. beer.

1925 E. Fraser & J. Gibbons Soldier & Sailor Words 224 Pish, whiskey. Any spirits.

1950 ‘Thirty-five’ Argot in G. Simes Dict. Austral. Underworld Slang (1993) 155/1 P-ss, beer.

Thus:

On the piss: Chiefly British, Australian, and New Zealand. on the piss: out drinking; engaged in a bout or bouts of heavy drinking. Conversely off the piss.

1929 F. Manning Middle Parts Fortune i. ii. 61 If any of you chaps go on the piss with Bourne, and he offers you a stirrup-cup, you can take it from me he has got you beat.

The adjective “pissed” - drunk - thus arrives as a result of drinking beer/alcohol.

Then there is

P2. a. Originally U.S. to —— the piss out of: to —— to an extreme degree. Cf. to —— the shit out of (a person or thing) at shit n. and adj. Phrases 2.

The idea is one of being subject to an unpleasant experience that causes involuntarily urination (or defecation).

1929 E. Dahlberg Bottom Dogs v. 98 He would knock the piss out of him.

1934 H. Miller Tropic of Cancer 83 That boss of mine, he bawls the piss out of me if I miss a semi-colon.

1971 H. S. Thompson Fear & Loathing in Las Vegas (1998) 24 I told him that we had a Vincent Black Shadow. That scared the piss out of him.

1998 Independent (Nexis) 7 Nov. 16 What irritates the piss out of me is when I see people pick up my book, and then just put it straight back down again.

Then there is

to take the piss (out of) b. colloquial (chiefly British, Australian, and New Zealand). to make fun (of), to mock, deride, satirize; = to take the mickey (out of) at mickey n.1 7.

1945 Penguin New Writing 26 49 The corporal..sat back in his corner looking a little offended. He thought I was taking the piss.

I suspect this is from the meaning of “piss” in two other phrases:

P1. a. piss and wind n. (and variants) empty talk, bombast.

1922 J. Joyce Ulysses ii. xii. [Cyclops] 314 All wind and piss like a tanyard cat.

And

b. piss and vinegar n. originally U.S. energy, vigour; youthful aggression.

1936 D. Barnes Nightwood: Orig. Version (1995) v. 71 The criers telling the price of wine to such effect that the dawn saw good clerks full of piss and vinegar.

in which “piss” is roughly equivalent to “spirit /bravado”

The verb in the meaning of to urinate, dates back to about 1300 but the newer meaning of to leave or go away seem to have originated in the 1930s:

to piss off 1. intransitive. To leave, go away. Frequently in imperative.The imperative is sometimes used simply to express disbelief, rather than dismissal (cf. to get away at get v. Phrasal verbs 1).

a1935 T. E. Lawrence Mint (1957) ii. xx. 186 You piss off, Pissquick.

1944 in G. Rock Hist. Amer. Field Service (1956) 510 Nobody seemed to know anything much, and we all figured bearers had pissed off.

The principle here is that "piss" is used in exactly the same aggressive and emphatic way as "bugger off" "fuck off" and the meaning of "urinate" is lost.

All quotes from or via OED.

I am wondering whether getting pissed in the drunken sense may have originated from being ‘pixilated’ Note the spelling, not pixelated but pixilated ie pixie-led, bewildered, whimsical, silly. I could imagine pixilated became a slurred, drunken ‘pixed’, then pissed

Just a thought?