https://www.selleckchem.com/products/rg108.html Patients with Alzheimer's disease (AD) have gut microbiome alterations compared with healthy controls. However, previous studies often assess AD patients who have been on medications or other interventions for the disease. Also, simultaneous determination of gut microbiome in patients with mild cognitive impairment (MCI) or AD in a study is rare. To determine whether there was a gut microbiome alteration in patients newly diagnosed with AD or MCI and whether the degree of gut microbiome alteration was more severe in patients with AD than patients with MCI. Fecal samples of 18 patients with AD, 20 patients with MCI, and 18 age-matched healthy controls were collected in the morning for 16S ribosomal RNA sequencing. No patient had medications or interventions for AD or MCI before the samples were collected. Although there was no difference in the microbial α-diversity among the three groups, patients with AD or MCI had increased β-diversity compared with healthy controls. Patients with AD had decreased B with AD or MCI have gut dysbiosis that includes the decrease of potentially protective microbiome, such as Bacteroides, and the increase of microbiome that can promote inflammation, such as Prevotella. Our results support a novel idea that the degree of gut dysbiosis is worsened with the disease stage from MCI to AD. While atypical antipsychotic medications are widely used for treating depressive disorders, their long-term effects on the risk of subsequent dementia have not been studied adequately. To investigate whether the risk of dementia differs according to the use of atypical antipsychotic drugs, and compare the effects of antipsychotic agents on dementia risk in individuals with late-life depressive disorders. A nationwide population-based retrospective cohort study was conducted using data from the National Health Insurance Service-Senior Cohort of South Korea. Atypical antipsychotic dosages were standardized usin