From my experience as a major anxiety sufferer, disassociation and depersonalization have been major problems in of themselves. I believe most people have experienced these things at some point in their lives, but if you haven't, you probably wont be able to understand it.
For me, I would describe derealization as coming on in attacks (like a panic attack). Like, it comes on all at once, and everything seems very confusing and unreal. I remember this one time in school... just sitting in the class room, and bam! (a derealization attack hit). This event happened early on in high school. If you have a real derealization attacks, it is one of the weirdest things you will ever experience. The best way I can describe it is that it feels like the soul completely (or almost) disconnects from its life. You can still observe things, but it has an incredible simplicity of focus, and nothing seems real (not even yourself).
Here, I'll just list the symptoms of a derealization attack:
-Intense mental fog
-Feeling disconnected
-Everything seems dream-like.
-Cognitive ability/control severely diminishes.
-Paranoia
-Euphoria
-Perceptual changes (you see both the world and self very differently).
-Fear of going insane/losing control.
Sounds like fun right? Probably not, lol. It can actually be one of the scariest experiences a person can have. But, it doesn't need to be scary. If we are able to recognize it when it comes, and be aware that it isn't permanent, it can be mind-expanding to an extent (although I wouldn't recommend it). The best thing to do is to not be afraid of derealization—if anxiety is the cause of the derealization, than being fearful of it will only exasperate it.
I've found the best cure for derealization is mindfulness. It seems to greatly help both anxiety and derealization. If you don't know what mindfulness is, basically it is a strong focus on the senses which leads to a stronger awareness of the self (which consequently reduces worrying thoughts, which typically is the cause of anxiety). Mindfulness can pull an anxious person out of the gutter (i.e. their imagination). If you're worried about things that are real, be mindful, all that is real can be seen there. Thoughts are thoughts, nothing more, nothing less—stop believing that your daydreams/dayterrors are real—they are
just thoughts, focus on reality.