Vortioxetine for the Treatment of Mood and Cognitive Symptoms in Frontotemporal Dementia

The goal of this clinical trial is to learn if vortioxetine improves mood symptoms and cognition in patients with early-stage behavioral variant Frontotemporal Dementia (bvFTD). The main questions this study aims to answer are: 1. Do individuals with mood symptoms and bvFTD have brain changes and cognitive profiles that differ compared to individuals without bvFTD? 2. Do mood symptoms and cognition improve following treatment with vortioxetine? Researchers will also determine whether there are changes in the brain associated with vortioxetine treatment. Participants will: * Undergo a screening visit that involves clinical assessments and laboratory tests * Undergo an initial brain magnetic resonance imaging (MRI) and fluorodeoxyglucose (18F) Positron Emission Tomography (FDG PET) scan before starting treatment with vortioxetine * Undergo memory and problem-solving tests before starting treatment with vortioxetine * Undergo approximately 12 weeks of treatment with vortioxetine, during which time there will be regular contact and assessments with the study psychiatrist * Undergo a repeat PET scan and repeat memory and problem-solving tests after 12 weeks of treatment with vortioxetine