Green’s Dictionary of Slang

hophead n.1

[hop n.3 + -head sfx (4)]
[late 19C+] (drugs)

1. an opium, morphine or heroin addict; thus hophead house, a place where addicts buy and take narcotics.

2. attrib. use of sense 1.

3. a cocaine addict.

4. the user of any drug.

5. a marijuana smoker.

6. an unstable person.