In the Sisters of the Flame fluff, the originals, and many of the others, were turned away from the Imperium by nannites in their brains invading their thoughts and breaking down their mental defences.

What I realized is that THAT, is not too far off from the control hallucinations some schizophrenics have.

Similarities:
-persistence [Both refuse to let up]
-commanding things [Both command the person to do something]
-inevitable giving in [Both are nearly impossible to resist, due to their persistence]

Differences
-timeframe [For the Sisters of the Flame it happens in minutes rather than days, weeks, months, or years for schizophrenics]
-technology vs biology [For the Sisters of the Flame it is technologically induced, for schizophrenics it is biologically induced]
-beliefs vs actions [The Sisters of the Flame were commanded to alter their beliefs and attitudes, schizophrenic command hallucinations tend to command an action]
-thoughts vs voice [The Sisters of the Flame had their internal thoughts turned against them, command hallucinations involve a command that is actually sensed, typically in the form of an auditory hallucination.]

Note, I'm not a doctor at all. Not a med student, not an intern, I have literally zero medical background.