I really like, and can relate to, the stages that you've described here.
I've had two occurences of HPPD in my life, one a lot more severe than the other. I won't bother going over the minor one, as the severe one relates most to your stages.
~3 Years ago, following multiple high-dose 5,MeO-DiPT trips within a period of around 2 week, culminating with a multidose trip that spanned 36 hours.
During the trip I experienced extreme dissociation, comparable to sub K-hole ketamine dose. The foxy faded, but this feeling continued for 6 months afterwards. Specifically, the physical perception of my body interacting with the world had a delay built in. I.e. I'd reach out my hand and touch something, and the sensation of touch would be delayed anywhere from 2-10 seconds. This made walking very difficult, as I'd constantly have the sensation of my mind being 10 seconds behind my body (I.e. I'd stop walking, but my mind would still be feeling the walking sensation from a few seconds earlier). A few times I fell down stairs as a result.
It took me months to learn how to compensate to this sensation, and by the time I fully got a handle on it, the HPPD had begun to fade. I've used psychadelics since this occurence, but always at below-typical doses, and constantly afraid that this might one day happen again, and be perminant.
capEr said:
Stage 1 - Realization (Once realized.. the person may become in a somewhat "uh oh" kind of attitude. They will realize what has happened to them and start getting depressed maybe.. bummer)
...
stage 5 - Reality (ahhh how i miss you.. hope to see you soon)