%0 Journal Article %T Unpacking Major Depressive Disorder: From Classification to Treatment Selection %A Amanda K. Ceniti %A Sidney H. Kennedy %J Archive of "Canadian Journal of Psychiatry. Revue Canadienne de Psychiatrie". %D 2018 %R 10.1177/0706743717748883 %X In the past decade, there has been a revival of the debate about diagnostic approaches in mental illness. In 1970, Robins and Guze1 described 5 distinct requirements to justify the diagnosis of a psychiatric syndrome. These involved 1) a consistent clustering of symptoms, 2) laboratory studies to establish a biological substrate, 3) relative specificity of symptoms to distinguish one disorder from another, 4) evidence from follow-up studies of a common course of illness, and 5) some evidence of genetic predisposition based on higher prevalence rates in the families of affected individuals. There are many potential benefits to this approach: internationally accepted taxonomy facilitates studies across multiple research areas, ranging from epidemiology and health economics to disease mechanisms, treatment outcome evaluations, and pursuit of new therapeutics %K major depressive disorder %K biomarkers %K heterogeneity %U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5912302/