After his initial facination and over exertion with mushrooms swim found himself seeing strange 30cm wide spots on walls that do not move as they should nor are they really part of the wall but kind of what your brain fills in for the blank spot in your vision. Interesting sure but swim was worried they were there all the same. These symptoms went away after about a week or two but swim has always had a lot of power over hypnagogic imagery especially while meditating in bed and would frequently notice the ground/grass/road warping and morphing subtly if he looked for long enough while stone sober so I just think some people are naturally more inclined to utilise that kind of self made imagry.

Hmm, well i'd not looked into it too much but i remember reading this on wikipedia (the o so trusted resource =/):

"The visual problems of HPPD can occur along with other mental ailments. Of these, the most prominent are anxiety, panic attacks, depersonalization disorder, and depression." Under co-existing problems. So i assumed the HPPD had something to do with this, it seems not but it does seem to in alot of cases go hand in hand with depression etc.