It is commonly – but wrongly – assumed that there are no important
differences between the clinical presentations of major depressive disorder
and bipolar depression. Here we compare clinical course variables and
depressive symptom profiles in a large sample of individuals with major
depressive disorder (n=593) and bipolar disorder
(n=443). Clinical characteristics associated with a
bipolar course included the presence of psychosis, diurnal mood variation
and hypersomnia during depressive episodes, and a greater number of shorter
depressive episodes. Such features should alert a clinician to a possible
bipolar course. This is important because optimal management is not the same
for bipolar and unipolar depression.