What exactly makes a show psychological?

I have been really struggling to differentiate between psychological anime and anime that just uses a lot of gore just for the sake of it. I get how to evaluate the difference between an anime that uses gore to really develop the characters vs. one that just uses gore for the sake of gore and entertainment. like what exactly would make Tokyo Ghoul any different from say the Promised Neverland? I know that Tokyo Ghoul has been on a lot of the "psychological" lists, and I'm definitely not accusing it of being poorly written, it's just that I'm having trouble finding the difference between the two. If anyone can help clarify that would be great!