TAC1 and Alzheimer disease: Psychological stress can provoke many cutaneous dermatoses associated with abnormal epidermal barrier function, such as AD.17 Stress involves different neuromediators, such as sensory neuropeptides, including the substance P-NK-1 receptor system, 11 and the serotonergic system, in, for example, raphe.18 There is a colocalization of serotonin and sensory neuropeptides in the nervous system.19