The special challenges of developing CNS drugs

The section in this book on Clinical Development is a mix of achieving goals by means of answering questions through scientific experimentation and following regulatory agreed guidelines. This is reflected by chapters describing the paths and guidelines for phase 1 (Chap. 16), answering bottom-up questions by utilising biomarkers for peripheral target engagement to determine dose selection for clinical phase 2 studies (Chap. 17). Subsequently, the chapter on microdosing of psychedelics uses the top-down perspective to find underpinning of a mechanism for data pointing to antidepressant effects of drugs taken out of the medical- or drug development context (Chap. 18). Finally, the chapter on interactions with FDA binds it altogether defining the best match for new data to medical needs and how to manage expectations in developers and regulators mutually and how to keep track of it (Chap. 19).