[I_Am_Nous]

If the demons control your body by abusing your brain and nerve impulses, it could be. Our bodies work through electrical signals and various neurotransmitters like serotonin, so an anti-psychotic that affects brain receptors could prevent such a "hotwiring".

Would it be any different than if aliens could beam signals to individual neurons to force you to do something? What about a skilled surgeon with an Arduino, or those seizure prevention circuits they can install?