Onset of Depressive Episodes Is Faster in Patients With Bipolar Versus Unipolar Depressive Disorder: Evidence From a Retrospective Comparative Study
Ulrich Hegerl, MD; Anja-Christine Bottner, Dipl Psych; Bettina Holtschmidt-Täschner, MD; Christoph Born, MD; Florian Seemüller, MD; Winfried Scheunemann, MD; Michael Schütze, MD; Heinz Grunze, MD; Verena Henkel, MD; Roland Mergl, PhD; and Jules Angst, MD
Objective: Depressive episodes can have
a very fast onset (< 1 hour) or start very slowly (>
1 month). This interesting aspect, pointing to
different neurophysiological pathomechanisms, has
not been systematically evaluated so far. The aim
of this study was to describe speed of onset of depressive episodes in a consecutive sample of
patients with at least 1 depressive episode and to investigate potential differences between
patients with major depression versus bipolar
affective disorders concerning this variable.
Method: We examined 158 consecutive
adult patients with major depression (N = 108) and bipolar disorder (N = 50) diagnosed according
to criteria of the International Statistical
Classification of Diseases, 10th revision, by applying
the structured Onset-of-Depression Inventory. Patients with acute critical life events preceding
the onset were excluded from final analyses. Data were collected between December 2001 and
January 2007.
Results: There was a significant positive
association between speed of onset of the present
depressive episode and that of the preceding
depressive episode (r = 0.66, p < .001). Patients
with bipolar disorder developed full-blown
depressive episodes significantly faster than patients
with major depression (p < .001): Whereas
depressive episodes began within 1 week in 58% of
patients with bipolar disorder, this was the case in
only 7.4% of patients with major depression.
Conclusion: Intraindividually, the speed
of onset of depression is similar across different
episodes. In the absence of acute critical life
events, fast onset of depressive episodes (within 1
week) is common in bipolar disorder but rare in
major depression. This aspect might be useful to
identify depressive episodes occurring within a bipolar affective illness and might characterize
a subgroup of patients with a distinct neurobiology.
J Clin Psychiatry 2008;69(7):1075-1080
© Copyright 2008 Physicians Postgraduate Press, Inc.