the fear that smoking makes of everything else
The dope scared him. It made him afraid. It wasn’t that he was afraid of the dope, it was that smoking it made him afraid of everything else. It had long since stopped being a release or relief or fun.
Context
The exact inversion at the late stage of a habit: the substance no longer relieves anything, it manufactures the dread it once medicated. He is not afraid of the drug — he is afraid of the whole world while on it, self-conscious to the point of hiding, and still committed to consuming it, which is the cage's signature: the thing that has stopped working is the thing he cannot stop doing.