The term „atypical depression“ is not clearly defi ned. The authors review the historical development of this concept. Several research groups (London group, Columbia group, Vienna group) have described some clinical characteristics and predictors of atypical depression and have contributed to the development of the the DSM-IV defi nition of the atypical features specifi ed for major depressive episode.

        Key words: atypical depression, atypical features, therapeutic response.