Ineffable Ontological Detanglement .: Introspective Assistance & Mental Analysis Manual
Dissociation, depersonalization and derealization are a bit of a cloudy murk within psychology. Most psychology people lump them into the same blur of "This person appears to be dissociated depersonalized drealized because they're a little out of it." Dissociation, they pretty much have all wrong all the way to the text book. What they call dissociation we place within brain fog, brain damage, the general spaciness that comes out of certain conditions and disorders, it's all over the place. They really generalized it and made it meaningless, it's the word for when your brain goes blurry. We'll just use it the proper drug way, it means outside of your thoughts and feelings, outside of your experience, however not in the manner that is depersonalized or derealized.
Depersonalization and derealization is the sensation that you are observing yourself and this world from outside of the self outside of the world, watching the movie that is your experience. At some point, pretty much everyone is going to feel it a little, you become overwhelmed and you need to take a little time outside of yourself to figure this thing out, because this thing is far too real to be real, this is not a real that you ever would have thought could be real, this is not a thing you would have ever expected this reality to produce for you.
Depersonalization is when something feel not quite right about you, derealization is when something feel not quite right about the world. Really overwhelming things can hit you as both, even though there's nothing really wrong with you, you still feel like you can't possibly be yourself.
When you live in this feeling, something is not right, you couldn't possibly be like this, the world couldn't possibly be like this, and you know it. And so you are not in this world. So many of you have a subtle underlying depersonalization or derealization and you don't realize it, you may have been in it your entire life to you this is just how it feels. There's the neutral baseline, that's where we all start, from here you'll probably drift into depersonalization or derealization.
You may drift in the other direction towards... Personalization or realization, where you feel even more in yourself, in the world, in this moment than you did when you were baseline. When you entered into the world not exactly fully understanding what it is, how you are to be. Psychedelic drugs will do it for you, existence maintains despite narrative will really do it for you, reading the work of The Society of Social Disturbance will really do it for you.