Understanding the cognitive impact of mental health issues, such as anxiety and depression, as discussed in prior chapters is the foundation for comprehending the complex nature of functional cognitive disorders (FCDs). This chapter provides an overview of the nature of this condition as well as the current science behind functional cognitive disorders within the context of diagnostics for neurodegenerative disorders. Advancing this understanding is important not only for providers of clinical care within this area, but also for patients and families that may have marked fearfulness related to forgetfulness.