Atypical depression: a valid subtype?

The concept of atypical depression has evolved over the past several decades, yet remains inadequately defined. As currently defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR), the main criterion of atypical depression is the presence of mood reactivity in combination with at least 2 of 4 secondary criteria (hypersomnia, hyperphagia and weight gain, leaden paralysis, and oversensitivity to criticism and rejection). The focus on mood reactivity as the primary distinguishing criterion remains questionable among researchers who have been unable to verify the primacy of this symptom in relation to the other diagnostic criteria for atypical depression. A model challenging the DSM-IV-TR definition of atypical depression has been developed, redefining the disorder as a dimensional nonmelancholic syndrome in which individuals with a personality subtype of "interpersonal rejection sensitivity" have a tendency toward the onset of anxiety disorders and depression, thereby exhibiting a variety of dysregulated emotional and self-consolatory responses. This reformulated definition of atypical depression (in arguing for the primacy of a personality style or rejection sensitivity as against mood reactivity) may lead to a better understanding and recognition of the disorder and its symptoms as well as other "spectrum" disorders within the scope of major depression.