Neurobiology of Severe Mood and Anxiety Disorders

Abstract

The most common mood disorder diagnoses are major depressive disorder (MDD); dysthymia, a less severe but more chronic form of depression akin to a mood trait; and bipolar disorder (BD), characterized by both depressive epi­sodes and episodes of mania and hypomania. The recurrent episodes or chronicity of the disorders suggests long-term alterations in neurobiological function, while the variability of symptomatic expression between episodes implies that the specific manifes­tation of an episode of a mood disorder is sensitive to state-dependent factors. Therefore, the pathophysiology of mood disorders should reflect both a common trait-dependent com­ponent and a more variable state-dependen..