An examination of the latest genetic and physiologic biomarker research and its application in viable therapeutic options for patients with Major Depressive Disorder (MDD) was the focus of a breakthrough poster presentation which debuted at the American Academy of Physician Assistants (AAPA) annual conference, IMPACT 2013. The poster and complete study findings were presented by Ian V. Mackey, M.S., P.A.-C, Physician Assistant, Rush University Medical Center.