Dr. Erick Messias, Chair of Psychiatry at Saint Louis University, introduces us to the world of psychiatric epidemiology. Learn how epidemiological figures (that show up on training exams) are derived, and explore how epidemiology can help us to understand the naturalistic course of psychiatric illness. We also delve into the history of our diagnostic system  and how it developed into the current model, and run through some of the most important findings to date in psychiatric epidemiology. Dr. Messias also explains how to approach every situation in life "as a 2 by 2 table," and we conclude with some wisdom about inserting meaning into daily psychiatric practice.