Green’s Dictionary of Slang

(drugs) intoxicated by drugs.

1933		Ersine Und. and Prison Sl. 48: junked up, junky. Full of dope.
1936		R. Chandler ‘Goldfish’ in Red Wind (1946) 150: Will you go out now, before he gets junked up for the evening?
1953		Anslinger & Tompkins Traffic In Narcotics 311: junked up. Under the influence of a drug.
1958		Murtagh & Harris Cast the First Stone 46: When a junkie’s loaded [...] she’s not interested in sex. When she’s not junked up, she’s too busy figuring ways to get the stuff she needs to think about sex.
1962		L. Block ‘Naked and the Deadly’ in One Night Stands (2008) 225: Smoky sounds shrieked out of a junked-up dying throat.
1978		(con. WWII) T. Sanchez Hollywoodland (1981) 123: It makes me sick to think he’ll die all junked up.
1985		(con. 1969–70) D. Bodey F.N.G. (1988) 230: ‘Forget it, man,’ the medic tells me. ‘He’s junked up.’.
1986		S. King It (1987) 387: It is a fresh thought, somehow clear-eyed, the sort of thought you might expect to have upon waking, when your mind isn’t all junked up.
1993		I. Welsh Trainspotting 292: Whenever they called round, he was lying junked on his mattress.
2002		D.H. Sterry Chicken (2003) 187: Jade was probably junked up [...] got herself whacked or jacked or smacked.
2012		(con. 1980s) I. Welsh Skagboys 70: Drawing attention tae yourself [...] wi a bagful ay skag might no be such a good idea.