ABSTRACT
INTRODUCTION Major Depressive Disorder (MDD) and Cyclical Mood Disorders, including Bipolar Disorder (BD) type I and II are among the more prevalent psychiatric conditions (1-3). They are associated with considerable morbidity, mortality, and functional impairment (3-5). Mood disorders are highly recurrent conditions, possibly associated with a progressive course. Recent epidemiologic studies suggest that repeated mood episodes and residual symptoms enhance the risk of future recurrence (6,7). Both a greater number of episodes and the longer duration of mood disorders may be risk factors for structural changes in the brain and systemic consequences (8,9). Although the prevalence of mood disorders appears to be lower in the elderly than in younger age groups, absolute numbers may be dramatically increasing due to an aging population (10). A recent Australian study (11), for example, noted that the relative frequency of bipolar disorder in individuals older than 65 years, increased from 1% to 11% between 1980 and 1998. Enhanced understanding of the neurobiologic specificities of late-life mood disorders may help us address this growing need.
