One of the richest avenues for nonverbal expression of emotion is emotional facial expression (EFE), which reflects inner psychic reality of an individual. It can be developed as a very important diagnostic index for psychiatric disorders. In this chapter, an attempt has been made to provide a systematic review of the following issues—the importance of facial expression as a diagnostic measure in psychiatric disorders, the effectiveness of computational models of facial action coding system (FACS) to aid in diagnosis, and, finally, the usefulness of computational approach on facial expression analysis as a measure of psychiatric diagnosis. The possibility of bringing objectivity in psychiatric diagnosis through computational model of EFEs will be discussed. © Springer India 2015.