AQP4 and major depressive disorder: 2019) and in the hippocampus following chronic corticosterone (Juszczak et al. 2025). This finding may be clinically relevant, as AQP4 expression is reduced in the post‐mortem orbitofrontal cortex (Rajkowska et al. 2013) and hippocampus (Medina et al. 2016) of patients with MDD and in the PFC of subjects who died of suicide (Piras et al. 2022).