Intrinsic teleportitis is no longer binary; you build it up by getting the intrinsic from multiple corpses. With more of it built up, the random teleports happen more frequently (essentially, “teleport opportunities” happen at the same rate the currently do; if you have N% teleportitis, you have an N% chance of teleporting on each opportunity).

However, the effect wears off over time and eventually fades completely (with some message like “You feel less jumpy”, so the hero knows they can’t Ctrl-T at will anymore).

Extrinsic teleportitis remains the same, triggering a teleport at the same rate it does currently.

This implementation meshes well with a partial intrinsic system like in SporkHack or EvilHack.