One of the avenues to enhance NMDAR function is via inhibiting D-amino acids oxidase (DAAO) activity.15 In an earlier randomized, double-masked, placebo-controlled trial,16 sodium benzoate, a pivotal DAAO inhibitor,17 significantly improved the cognitive function of patients with early-phase AD (without BPSD), with a mean dose of 716.7 mg/d at week 24. This evidence concerns the gene DAO and Alzheimer disease.