A Study of LY3303560 in Participants With Mild Cognitive Impairment or Alzheimer's Disease

Inclusion Criteria: * Mild Cognitive Impairment (MCI) due to Alzheimer's Disease (AD) or mild-to-moderate AD based on National Institute of Aging and Alzheimer's Association diagnostic criteria * Female participants: women not of child-bearing potential may participate, and include those who are: * Infertile due to surgical sterilisation (hysterectomy, bilateral oophorectomy, or for countries outside of Japan, tubal ligation), congenital anomaly such as mullerian agenesis; or * Postmenopausal defined as women at least 50 years of age with an intact uterus who have not taken hormones or oral contraceptives within 1 year, who have had either cessation of menses for at least 1 year, or 6 to 12 months of spontaneous amenorrhea with follicle-stimulating greater than (\>) 40 milli-international units per millilitre (mIU/mL) * Have a body weight of at least 50 kilogram (kg) (except for Japanese sites) and have a body mass index (BMI) of 18.0 to 35.0 kilogram per meter square (kg/m²) (for all sites), inclusive, at screening Exclusion Criteria: * Are currently enrolled in a clinical trial involving an investigational product (IP) or any other type of medical research judged not to be scientifically or medically compatible with this study * Have participated, within the last 30 days (3 months and 4 months for sites in the European Union \[EU\] and Japan, respectively) in a clinical trial involving an IP. If the previous IP has a long half-life, 3 months (4 months for sites in J…