The Long-term Natural History of the Weekly Symptomatic Status of Bipolar I Disorder

Abstract

KRAEPELIN¹ HAD described manic-depressive insanity as a cyclical illness. Until recently, following his lead, clinical and research attention concerning mood disorders was concentrated on the most severe syndromal manifestations of these disorders, ie, manic and major depressive episodes (MDE).^2-9 However, recent evidence suggests that the concept of bipolar I disorder (BP-I) with episode-free periods of euthymia punctuated by syndromal MDE and mania is inadequate.^10-12 Analyses of weekly symptomatic status during the long-term course of another mood disorder, unipolar MDD,¹² has shown that, although this illness has traditionally been examined primarily in terms of the onset, remission, and relapse of MDEs, minor and subsyndromal depressive symptoms dominate its long-term course by nearly a 3:1 ratio (43% vs 15% of follow-up weeks). Patients with unipolar MDD were found to be symptomatic during 60% of the follow-up period and to experience a changeable course in which major, minor, and subsyndromal depressive symptoms alternated within the same patient over time. In brief, unipolar MDD is expressed longitudinally as a dimensional illness involving the full spectrum of depressive symptom severity.