Green’s Dictionary of Slang

a drug user.

1927		F.M. Thrasher Gang 340: ‘Some special habit or aptitude [...] Dopey (drug addict)’.
1930		J. Lait Gangster Girl 166: The cokies an’ the dopies who pick up this stuff.
1931		P.J. Wolfson Bodies are Dust (2019) [ebook] ‘Shut up, you lousy dopey,’ James said. ‘I’m a dopey! Why—you lousy—’.
1963		C. Cooper Jr ‘Not We Many’ in Black! (1996) 289: Yes, dopeys and drugmen.
1967		C. Cooper Jr Farm (1968) 22: Tamerlane was a big black dumpy dopie.
1971		E.E. Landy Underground Dict. (1972).