Contemporary medicine believes that depression is a psychological disorder and that its etiology lies mainly in biological dysfunction. However, many authors refer to questionable parts of such a paradigm.
Discussed as problematic are e.g. ambiguity of possible neuropathology as a cause of this affective state or rather low effectiveness of the treatment. These authors state that a posssible explanation could lie in heterogeneity, that depression may not be a unified syndrom.
In this review we introduce evolutionary perspective of depression, which is considered to be one of the possible explanations of the heterogeneity problem. Under the adaptation theory, at least a part of depressive cases may in be fact healthy reactions to adversity.
According to several selected adaptive hypotheses, we describe possible functions of depressive symptoms We conclude with a discussion of possible treatment implications.