Green’s Dictionary of Slang

(drugs) a smoker of marijuana or hashish.

1957		J. Gelber Connection 38: One of them turns out to be a pot-head.
1963		M. Braly Shake Him Till He Rattles (1964) 83: But you look clean as far as the heavy goes. That’s where the real heat is. As for one pothead more or less ...
1970		letter in Edelman Dear America (1985) 6 Sept. 150: The supposed ‘pot heads’ are much easier to work with, and more pleasant [...] and more intelligent than the redneck faction of boozers!
1980		(con. 1940s–60s) H. Huncke ‘Spencer’s Pad’ in Eve. Sun Turned Crimson (1980) in Huncke Reader (1998) 98: Pimps and wise guys and junkies and potheads and just people.
1985		‘Thommo’ Dict. Aus. Swearing & Sex Sayings 101: POT HEAD — One who smokes marijuana frequently.
1998		(con. 1986) G. Pelecanos Sweet Forever 75: A new generation of kids [...] trying to separate themselves from the beards and potheads who came before them.
2000		Guardian Rev. 12 May 7: By the time potheads were appearing regularly in the movies it was the 80s.
2004		Mad mag. Oct. 45: The city is engulfed in a perpetual haze of smoke from all the potheads.
2007		L. Redhead Cherry Pie [ebook] It never ceased to amaze me, the way potheads immediately recognised their own kind.
2010		K. Richards Life 434: Oh you wouldn’t understand. Oh really? I heard that phrase from potheads many years ago.
2015		P. Beatty Sellout (2016) 84: ‘You know who was a pothead,’ he said, refusing the doobage.