I was rewatching Miller’s Crossing wherein John Turturro’s character refers to Steve Buschemi’s character actions as explainable by “skinful of hop, headful of boogiemen”. In Boardwalk Empire, in one episode, the characters seem to insinuate that it isn’t heroin. If that’s true, what did it refer to?
Thanks,
Rob
Well, I always thought it refereed to the hops in beer. My assumption was that hops look sort of like the buds in marijuana, so that’s why hophead meant a drug user.
No idea though, so really just posted to see what the answer is. 
Does start as opium user, but the term, just like the drug became refined over the years and by no later than the 40s referred to morphine/heroin addicts. I have neveer seen its use in popular fiction to mean anything other than herion/morphine junkies.
Why is hop slang for opium?
Thanks,
Rob
A quick google turns up this book which indicates that a Cantonese slang for the drug, nga pin meaning crow shit, was pronounced something like ha peen, which pretty clearly could end up as both “hop” and “opium”.
This backs up that origin: hop | Etymology, origin and meaning of hop by etymonline
I’d tend to trust Joh Lighter, the editor of the Historical Dictionary of Ameican Slang.
He says that it’s more likely derived from “Hop-Toy” (1881), Anglo-Cantonese for “container for opium.”
Less likely from the pidgin forms of Mandarin ho ping / Cantonese nga pin (1886).