Major Depressive Disorder
A discrete episode of persistently low mood and/or loss of interest lasting at least two weeks, accompanied by a cluster of physical, cognitive, and behavioral changes severe enough to impair functioning.
Depressive Disorders
Conditions sharing a core feature of sad, empty, or irritable mood accompanied by changes that significantly affect functioning.
Disorders in this family
Persistent Depressive Disorder (Dysthymia)
A chronic, lower-grade depressive mood present for most of the day, more days than not, for at least two years in adults (one year in children/adolescents) -- persistence rather than intensity is the defining feature.
Case Lab vignettes
The Exam Season Crash
Distinguish a major depressive episode from normal adjustment stress and from a bipolar-spectrum presentation.