The purpose of this study is to study the effect of lanabecestat on how the body absorbs and processes 3 other medications, midazolam, simvastatin and donepezil and how these 3 medications affect lanabecestat when they are taken together. This study is in 2 cohorts, Cohort A is approximately 44 days long and Cohort B about 70 days only. The screening visit is required within 30 days prior to the start on the study