Castleman:
Is there a rule regarding traumas, disorders, malignancies, etc along the lines of "old habits" or something like that, where if you get another trauma, et al after getting rid of one in the past it's likely to be the one you had before?
If so, where in the book is it?
Yup. Two sources:
Ascension under "A Mind Repurposed" along with the one regarding Corruption Points/mutations. In both of those they talk about how, as the Throne Agent gains more Corruption/Insanity Points, they begin to fall into "familiar patterns" and the old insanities/malignancies/mutations they had begin to resurface.
Inquisitor's Handbook under the Mind-Cleansed character creation there's a large section about how the old personality is merely overwritten and never truly erased. Thus the person still has fragment of who they once were resting within them.
Hope that helps Castle and I'll be looking forwards to hearing back from you ;).