P2RX4 and attention deficit-hyperactivity disorder: Since P2X4 is involved in various neurological and psychiatric disorders (Lindberg et al., 2015; Duveau et al., 2020; Montilla et al., 2020), we made the hypothesis that P2X4 could play an important role in ADHD symptoms and comorbid pain by modulating microglia activation and neuronal transmission in the ACC and/or the PI.