Prescribing of antidepressant treatment (ADT) for major depressive disorder (MDD) has increased in quantity and popularity over the last two decades. This is likely due to the approval of safer medications, better education of clinicians and their patients, direct-to-consumer marketing practices, and less stigma associated with those taking ADT. This trend has also been met with some controversy, however, as the ongoing safety and effectiveness of these treatments have at times been called into question. This paper discusses the differing levels of evidence that support the use of ADT based on (A) Food and Drug Administration approvals, (B) data from randomized controlled trials or meta-analyses and, where these are not available, the authors discuss and apply, (C) theoretical pharmacodynamic principles to justify antidepressant choice in the treatment of MDD patients. The final section discusses standard psychopharmacology guideline approaches to better alert the reader as to which practices are commonplace compared with those which are more outside of the standard of care.