For instance, previous research on monotherapies in rodents did report different results within male and female animals: a recent study on treatments for post-traumatic stress disorder found differential effects caused by citalopram on fear associated memory in female mice compared to males [55]; similarly, different outcomes were found after administration of metoprolol: this beta-blocker impaired performance in Morris Water Maze and FC tests in males of the APP Alzheimer's Disease mouse model and wild-types but not in females [56]. This evidence concerns the gene APP and post-traumatic stress disorder.