Kotagal V, et al. - Researchers ascertained the relationships between serotoninergic neurotransmission and cerebral β-amyloid peptide (Aβ) burden in Parkinson disease (PD). Serotoninergic medication use for ≥6 months associated with a lower level of cerebrospinal fluid (CSF) Aβ-42 in the baseline Parkinson's Progression Markers Initiative (PPMI) analysis. Baseline serotoninergic medication use associated with a reduced risk of cognitive decline after controlling for covariates in the longitudinal PPMI model. According to the findings obtained, cortical Aβ burden in PD associates inversely with serotoninergic innervation. Results of this study suggested that serotoninergic medications could alter Aβ metabolism and decrease the risk of PD cognitive decline.