I think the pathology of HPPD is too case sensitive and complex to be cured with a "magic bullet" 5HT2-a receptor antagonist. I understand why you might believe this to be an option, but in my experience, approaching treatment with narrow vision, so to speak, (no pun intended), is doomed to fail. Most of the substances that have landed many of us in this predicament have complex pharmacological profiles, some of which, either are incomplete, or we are unaware that they are incomplete. There is still much to be learned. Looking at the situation with a broader perspective enveloping every single receptor system affected, and possible/existing downstream effects of each individual drug, compiling that data, cross-referencing symptoms, drawing corresponding similarities, and creating a possible causative profile for each individual drug should be the goal. Though I have another theory, albeit, also case sensitive, but I believe it to possibly be applicable to the situations of some other individuals. Quick summation - Infectious disease, undiscovered or otherwise (lyme disease, bartonella, babesiosis, etc...) may be an induction precursor/catalyst to HPPD. The idea being that the brain's neurochemistry and the body's CNS is already weakened/unstable, and the ingestion of a drug, (especially neurotoxic RC's), can further the damage done to the brain/CNS by the illness, causing further and much more significant chaos to ensue. The reason I have so much invested in this particular theory is because I personally suffer from Lyme disease/bartonella, and it became abundantly clear to me that my HPPD would have never occurred had I been disease-free. I don't feel like going into too much more detail, but suffice to say, treating those diseases vastly improved my HPPD, and I'm certain that if I weren't such a late stage patient, and I wasn't ingesting cannabis, coffee and tobacco on a regular basis, my hppd would be entirely gone. I have come close to ridding it entirely in the past, but it has become less and less of a priority, as it is not nearly as severe as it used to be, and I have simply gotten used to it. Just my half baked thoughts. ha Take it as you will.