Diphenhydramine is one of the drugs known to cause HPPD when taken in high doses. I used to trip on diphenhydramine by taking 400+ milligrams and it caused hallucinations, visual disturbances, trouble speaking and trouble walking and much other fucked up shit. I already had HPPD when I started abusing diphenhydramine but diphenhydramine made all of my symptoms 10 times worse. made my HPPD go from a minor case to a very severe case with depersonalization ! the symptoms you just discussed are of a very weak haze and you shouldn't be taking 100 fucking milligrams ! i only take diphenhydramine now when I am sick but in the correct dosage