The fields of neuroscience and mental health seem to be on the rise… And if you don’t know all of the fancy-sounding terms that are being batted around, then don’t despair! Most people would be hard pressed to explain the differences between a psychologist and a psychiatrist, much less describe the role of a neuropsychologist. So today, my goal is simply to remove any assumptions and start from the very beginning. PSYCHIATRY. A psychiatrist is a medical doctor (M.D. or D.O.)