Hal's history-of-his-drug-use passages were cut repeatedly — Wallace kept removing explicit Hal-drug exposition.

This is material that was cut: present in a draft, absent from the published novel.

In the published book. This material does not appear in the published book. Published remnant = Hal's secrecy material (scene 2 area, endnote-scene n321)

Evidence. A single source reports this. Documented by Steven Moore's first-draft collation ("cut repeatedly").

Bears on. This difference bears on the following open questions: what broke Hal if not (only) DMZ; damage vs. emergence; did Hal ingest DMZ, and by what route (dosed / endogenous / self / none).

Further notes. Deliberate authorial obscuring of exactly the evidence the Hal debates need — the opacity is engineered, which is itself evidence about how to weight arguments from silence.