What you have is Visual Snow and not HPPD... but is almost the same. But when you say you doctor you have visual snow he will be maybe more "good" to you and dont judge you for taking drugs (that actually you never did) This happened to me... Anyway look for HPPD works Benzodiazepines (but are pretty adictive) and some anticonvulsives just like Keppra or Lamictal. What makes hppd worst is Antipsychotics just like Risperidone. Antidepressives just like SSRI'S (Sertraline, Prozac, Paxil) make that your symptoms flare up but just ik the begining of treatmente then they get back to baseline. This is all I know since I had HPPD and did read a lot of forums and groups and official information too. Hope it helps!