Studies have shown that Sinemet can improve symptoms of HPPD and I know some of the members on the forum have found this to be true in their own experiences. This poses a question.. All along, antipsychotics have been cautioned against when it comes to treating HPPD because of their antagonization of the 5-HT2a receptor. Could this be totally wrong? Could the reason antipsychotics worsen HPPD have to do with their lowering of dopamine? It would seem a likely possibility considering that by raising dopamine, Sinemet ameliorates many of the symptoms, including depersonalization which antipsychotics also tend to exacerbate. I'd love some input on this!