The present document is the final of three parts of a review that focuses on recent data from clinical and animal research concerning the biochemical bases of depressive disorders, diagnosis, and treatment. Various treatments for depression, including psychotherapy, pharmacological, and somatic treatments, will be described in this third part. Also, some of the controversies in the field, as well as a summary of the most salient points of the review, will be discussed. Previous sections of this review dealt with the classification of depressive disorders and research techniques for studying the biochemical mechanisms of these disorders (Part I) and various transmitter/receptor theories of depressive disorder (Part II).