As DLGAP1 encoding protein SAPAP interacted with PSD95 encoded by DLG4, that constituted NMDA receptor‐associated postsynaptic density proteins, DLG4 was reported to be a predictor of cognitive deficits (Sultana et al., 2009; Whitfield et al., 2014), while NMDA was suggested for the association with ADHD and prefrontal dysfunction, we tested the association of DLGAP1‐DLG4‐NMDA pathway with cognitive flexibility and ADHD symptom. The gene discussed is DLG4; the disease is attention deficit-hyperactivity disorder.