Abstract Background and Hypothesis Visual hallucinations (VH) are a core symptom of both Lewy body diseases (LBDs; eg, Parkinson’s disease and dementia with Lewy bodies) and serotonergic psychedelics (SPs; eg, psilocybin and mescaline). While these conditions differ in etiology, overlapping phenomenology, and neural mechanisms suggest shared pathways. This review explores similarities and...