DAO and Mental deterioration: In fact, there are overlapping pathophysiology and clinical manifestations between AD and schizophrenia: both reveal cognitive decline (McKhann et al., 1984; Lin et al., 2014c), psychotic and behavioral symptoms (Lin and Lane, 2019a; Kendler, 2020), implication with NMDAR pathogenesis (Yao and Zhou, 2017; Lin and Lane, 2019b), and clinical improvement by DAAO inhibition (Harrison, 2018; Lin et al., 2020a).