Age of onset and the prospectively observed course of illness in bipolar disorder

Abstract

BackgroundTo test the validity of age-of-onset grouping in bipolar disorder through the use of prospectively observed time in mood episodes. MethodsAge-of-onset ranges from prior admixture analyses were used to divide 427 individuals with bipolar I or bipolar II disorders into early-, middle- and late- onset groups. These were compared by the proportions of weeks depressed and manic or hypomanic during a mean (SD) prospective follow-up of 17.4 (8.4) years. ResultsAs predicted, the group with the earliest onsets reported at intake more previous episodes, suicide attempts and panic attacks. An early age of onset, but not current age, was predictive of significantly more time in depressive episodes during follow-up but was not predictive of time in manic or hypomanic episodes. LimitationsThis was a naturalistic study with no control of treatment so variability in treatment may have obscured relationships between predictors and outcomes. Age of onset was retrospectively determined and subject to inaccuracies in recall. ConclusionsAn early age of onset conveys, to a modest degree, a poorer prognosis as expressed in more depressive morbidity.