Flashback phenomena after administration of LSD and psilocybin in controlled studies with healthy participants Felix Müller, Elias Kraus, Friederike Holze, Anna Becker, Laura Ley, Yasmin Schmid, Patrick Vizeli, Matthias E. Liechti, Stefan Borgwardt Psychopharmacology, 2022, 1-11. doi : 10.1007/s00213-022-06066-z   Abstract Background : LSD and psilocybin are increasingly used in phase I trials and evaluated as therapeutic agents for mental disorders. The phenomenon of reoccurring drug-like experiences after the acute substance effects have worn off was described for both substances and especially attributed to LSD. According to the DSM-V, the persisting and distressing manifestation of these experiences is called hallucinogen-persisting perception disorder (HPPD). Data on both conditions [...]