Do psychiatric illnesses turn off body's normal "gut instinct" or discernment response- like "this person is bad" etc etc?

Gut reactions: Psychiatric illness doesn't really turn gut instincts "off, " but it can confuse them. For instance, i know people who keep returning to violent relationships, even though logic would tell them to steer clear. Also childhood trauma can make you think love = abuse, so that what's actually "bad" looks like it's "good." they meet someone who treats them meanly, and are immediately entranced.

Instinct: Intuition is an innate human ability. Some people are more tuned in. If psych illness is severe enough can keeps you preoccupied it may be lessened.

No, they do not: In fact, by stabilizing your mood, thought processes, and behavior, you are actually much better at detecting such things while you are on medication. Best wishes.