Important Please Read:
I've been reading a lot and I think that there may be a possibility and link to a nutritional deficiency in HPPD, which realistically would assess the strange variable nature of this condition. If you at immediate glance question the severity of nutritional deficiencies just look up Pellagra and Scurvy, they eventually die if its not corrected. Most vitamins are antioxidants and neutralize free radicals, and hallucinogens stimulate neuronal metabolism leading to excess free radicals. When free radicals are excessive and deficiencies have occurred of said nutrients, the free radicals can no longer be controlled and spiral out of control, damaging surrounding tissues. These tissues in turn become inflamed and even due to their neuronal nature start becoming demyelinated, this is the explanation for the very mild incidence rate of white matter hyperintensities in HPPD MRIs, however not in all. These demyelinations under the given uncorrected circumstances cannot or very difficulty be repaired, unless the deficiency is corrected. The deficiency would also explain why some people never get HPPD, even with extreme doses of LSD use, they have plenty of reserves of the free radical neutralizing vitamin necessary. It would also explain why some people only get it after multiple uses of hallucinogens, eventually they deplete the vitamin, whichever it may be. It would also explain the relationship with alcohol initiating HPPD in people who did hallucinogens a month or two beforehand, alcohol also may variably deplete the vitamin. It also could explain the spontaneous recovery of some few individuals that have reported it. It would also explain why multiple different drugs initiate HPPD, from alcohol, to weed, to hallucinogens, they all stimulate neuronal metabolism by excitation and or drain certain vitamins that are vital to neuronal functioning and maintenance, hence the symptoms. Also some of these vitamins are absolutely crucial to proper neuronal function and a deficiency only of some, like Vitamin B3 can lead to psychosis. I could elaborate further on this but will refrain for the sake of brevity.
If anyone in the slightest bit thinks this to be a complete impossibility, like i said look up pellagra and the mental health issues they have, and even vitamin b12 deficiencies cause demyelination of axons. And even some may argue that the nutritional RDA is met by common foods, this assuredly isn't true, and proven not to be true, especially in the cases of drug use and alcoholism, there are definitely related deficiencies common with these habits.
I think that this possibility has some of the most merit than any of my other ideas, so if anyone would like to try and experiment as to whether a treatment will work, then they should get a full spectrum b vitamin complex(All B-vitamins known). and also Vitamin C. The B complex should be higher than the average listed RDA, as typically it wouldn't be enough. And the vitamin C needs to be at the very least 1000mg a day. Treatment should be carried out for 6 months.
I wont get in to all the details as to everything correlative with vitamins, their deficiencies, and their importance, but if anyone cares to know more, they can read "How to Feel Better and Live Longer" by Linus Pauling, two time Nobel Prize winner and profession chemist. Even if the treatments don't work, at the very least it will certainly improve the health of the person taking these vitamins.
If its not that then we may have some genetic defect.
If you do try this treatment please report that you are trying it, and also please absolutely follow up with your results in the future. Thank you!
Edit: I also forgot to add that I read that taking large doses of vitamin B3 will end an LSD trip within roughly 30 minutes, which shows a specific relationship with it and hallucinations, but not however with LSD diectly as far as I can conjecture, as LSD usually is metabolized within 30 minutes of hitting the blood stream. However the hallucinations continue for hours, which shows that the actual cause of hallucinations are downstream from LSD metabolism, and have a direct correlation with Niacin(b3) if thats true. I didn't read it from what I would consider an absolute reliable source, but there very well may be some merit and truth to the statement, as it wasn't an unreputable source either. If anyone else knows more feel free to share.