Hi.
I've had moderate HPPD for 5 years now. Good days are - hppd doesn't even come to my mind, bad days are severe anxiety, depersonalization and "weird" feelings (I think everybody with HPPD knows what I'm talking about). I drink alcohol 1-2 times a week, when I'm drunk I don't even know I have HPPD but the hangovers - they're insane. Sometimes when hung over, without any benzo (I don't use benzos regularly, only when things are going too far...) I find myself getting brain zaps, suffering insomnia and paranoia/fear.
Other drugs: I've used some RC phenetylamines in moderate amounts - the trip sometimes got really weird and out of control but in the long run, nothing made my HPPD any worse. However, with the high not being as enjoyable as without HPPD, the psychedelic phenetylamines I really don't care for. I've been very careful with tryptamines - shrooms started my HPPD - I only took 4-AcO-MIPT one time, the trip was not enjoyable, but not a horror trip either, no permanent damage done. I used MDMA crystals quite often for some time and even tho it made my visuals worse for a few days eventually it subsided. The MDMA experience is a lot less enjoyable for me since HPPD. The comeup is very chaotic, it's really difficult to pass into that relaxed state and sometimes I am completly unable to "let myself go". I like 4-fluoroamphetamine, but the comedowns are difficult.
Recently I discovered ketamine and MXE and I really like dissociatives, preferably K. Even though it does produce vivid imagery and extremely psychedelic state it NEVER worsened my HPPD, visuals-, dp/dr-, or anxiety-wise, therefore I put them in the "safe" category.
I really liked weed before HPPD but now I don't smoke it that much, because it simply isn't that enjoyable and seems to worsen my anxiety almost all the time (except when I'm drunk;) so the daily basis is gone... A puff or two from a joint is o.k. but two fat bongs like before...not anymore. (Makes me sad, I really liked weed)
Keep in mind - your brain can behave differently than mine, don't take my experiences as knowledge base for yrself and do your research carefully. If you feel you are really fucked, then stop drugs, it's the best you can do. Give yourself a break, clear your head and maybe some day....
Good luck to you all