Behavioral science is an extremely high-yield, yet often overlooked, subject on the USMLE Step 1. Understanding important behavioral science concepts and being able to apply them to test questions can significantly increase your score. Deja Review: Behavioral Sciences is the perfect format to study behavioral science material; it helps you rapidly review material you know as well as fill-in gaps in your knowledge. In this second edition of Deja Review: Behavioral Sciences I have highlighted high-yield concepts such as psychiatric disorders and developmental milestones while still keeping the content comprehensive enough to use during your preclinical course and clerkship. Epidemiology and biostatistics are often tested on the USMLE—this.