hook, n.² — Green’s Dictionary of Slang

hook n.²

(drugs) an addiction.

1972		P. Thomas Savior 7: I mean this was his first hook and...he made it to...the ‘kick factory’ [HDAS].
1996		(con. 1964-65) B. Thorpe Sex and Thugs and Rock ’n’ Roll 148: The other thing good smack always did [...] was make her horny and that was a big part of Natalie’s hook.

off the hook

(US drugs) ceasing to take narcotic drugs.

1990

(con. 1930s–60s) H. Huncke Guilty of Everything (1998) 236: That [the death of a dealer] took me off the hook pretty fast.

on the hook

(drugs) addicted to a drug.

1952		(con. 1948) G. Mandel Flee the Angry Strangers 244: Dinch, you get kids on the hook for Buster?
1956		‘Raymond Thorp’ Viper 124: I spotted some cats who might have been on the hook [...] human wrecks with blank stares.
1959		W. Brown Teen-Age Mafia 128: For the first week the stuff was free. By then he was on the hook.