If a patient meets all five criteria for Persistent Depressive Disorder, what is the correct diagnosis?

• A. Persistent Depressive Disorder
• B. Bipolar Disorder
• C. Major Depressive Disorder
• D. Cyclothymic Disorder

Answer: (C)

This item tests how we tell apart a chronic mood disturbance from a discrete major depressive episode. Major depressive disorder is diagnosed when a person has a major depressive episode, defined as at least five of the core depressive symptoms occurring during a two-week period, with either depressed mood or anhedonia, and enough impairment. Persistent depressive disorder (dysthymia) is a separate, chronic condition characterized by depressed mood most of the day for most days over at least two years (one year for children), plus at least two additional depressive symptoms, with symptoms present for long durations and without long gaps.

If someone truly meets all five criteria for a depressive episode, that corresponds to a major depressive episode, which leads to the diagnosis of Major Depressive Disorder, even if there is a longer-standing mood disturbance. Persistent depressive disorder would be the diagnosis when the mood disturbance is chronic but does not reach the full criteria for a major depressive episode most of the time; a major depressive episode can occur on top of dysthymia, but that would carry a specifier indicating intermittent MDD on a background of PDD.