AQP4 and Alzheimer disease: Xia et al. observed that CUMS reduces AQP-4 expression in the cortex and hippocampus, and hypothesized that this may explain the altered glymphatic clearance, and the subsequent accumulation of Aβ42 in the brain, thus demonstrating that the dysfunction of the glymphatic system after injury by depressive disorder is a critical element in the development of AD, and the antidepressant fluoxetine may reverse this pathogenesis under chronic stress.