5htp cannot pass the blood/brain barrier, so it metabolizes into serotonin in your blood stream, causing to much of it to become active. It's a myth that it actually produces more serotonin within the brain. That is why 5htp can worsen the symptoms of hppd. Lets not forget that 5htp is technically a psychedelic substance (tryptamine). Lets not forget one of the main causes of "H"ppd.
5htp caused my anxiety due to hppd to worsen. I was almost never anxious before 5htp. It would almost always be visual distortions. Now I only sleep every 2-3rd day. I find myself pacing constantly. I'll be with friends watching tv, and randomly stand up and pace for a few mins. I have to pace at least every 10 mins or i feel like im going to go insane. If I'm sitting at my computer ill walk out of the room, and instantly back in. I feel like I'm stuck in limbo for the rest of my life now.
I will admit xanax does help my anxiety as long as i take it every 4 hours. That's just not safe, so i only take it twice a week. I still feel anxious every day, but It's better than being addicted to drugs.
PS- I used to love having hppd. I thought it was kind of entertaining. The symptoms began to fade once, and i was kind of disappointed. then one day they just came rushing me like never before.