Atypical depression: Current status and relevance to melancholia

Objective: The Diagnostic and Statistical Manual, Fourth Edition (DSM-IV, 1994) included atypical features as an illness specifier for major depression and dysthymia. We asked whether subsequent literature supported its validity and addressed the relationship between depression with atypical features and melancholia. Method: Literature review focusing on studies addressing the validity of atypical depression, supplemented by the authors' previously unpublished data. Results: Most studies support the discriminant validity of depression with atypical features relative to melancholia and depression having neither melancholic nor atypical features. However, studies addressing illness course suggest that criteria for depression with atypical features define a heterogeneous patient population. Conclusion: DSM-IV criteria for depression with atypical features define a valid, but heterogeneous disorder. Criteria including age of onset and chronicity may define a more homogeneous group that is distinct from both melancholia and other depressed patients.