Although "double depression"--major depressive disorder superimposed on
an underlying chronic depression--is a frequent phenomenon, the concept has
not been well formulated clinically and has rarely been described in the
research literature. The authors found that 1) 26% of l0l patients who met
the criteria for major depressive disorder had an underlying chronic
depressive disorder of at least 2 years' duration, 2) "recovery" rates for
patients with superimposed depression differed greatly depending on whether
recovery was defined as recovery from the major depressive disorder only or
recovery from both disorders, and 3) patients with superimposed depression
relapsed at a significantly higher rate immediately after recovery from the
acute episode of depression than did patients without superimposed
depression.Abstract Teaser