Insight once removed: When, because of mental illness, you can’t tell if your thoughts and behaviour are appropriate or not, but you at least know that you don’t know. You can thus take appropriate measures, i.e. stay inside and don’t talk to anyone, despite not having a fracking clue what is going on.
Uncertain insight: Where you think you understand how your illness changes your perception of reality, most of the time, probably, but then you can’t be sure that you aren’t simply deluding yourself.
False or insufficient insight: You believe yourself to be a mildly crazy person who has reasonably good insight into their condition. In reality however you are quite a lot crazier than you think, and there are some aspects of your mental illness that you are completely unaware of. Your supposed ‘insight’ mostly serves to deepen your denial.
Insight shock: When you gain new insight into your mental illness which forces you to re-evaluate what kind of a person you are and what motivates you. You see many of your past experiences in a new light: events that at the time seemed random now fit into an over-arching pattern, and with sudden and painful clarity you realise that actions you took in the past, that seemed entirely reasonable at the time, were in fact completely freaking batshit insane. This may lead to a lot of cringeing, face-palming, sitting up abruptly in bed and saying out loud: “Wait, when that thing happened 7 years ago, did I really – oh shit, I really did that. Oh no oh no oh no. And that means – ooooooooooooh. Ohh ohhh ohhh. Oh shit. Oh shit oh shit oh shit.” This can last for weeks or months.
Actual insight: Maybe it exists. But how would you know?