A history of the concept of atypical depression.

Atypical depression is defined as a type of depression that responds preferentially to monoamine oxidase inhibitors. In addition to mood reactivity, symptoms of atypical depression include hypersomnia, hyperphagia or weight gain, leaden paralysis, and a long-standing pattern of rejection sensitivity or interpersonal sensitivity. Over the years, atypical depression has been associated with or identified as nonendogenous depression, anxiety, reverse vegetative shift, chronic pain, bipolar disorder, and rejection sensitivity. This presentation discusses the history of the identification of atypical depression, starting with its initial identification in 1959, and describes the important studies of atypical depression and its treatment by various research groups during the past 50 years. The presentation concludes by differentiating between typical and atypical depression and detailing of some of the clinical characteristics of atypical depression.