Course of Bipolar Disorder in Adults and Children
KATHLEEN RIES MERIKANGAS, NICOLE JAMESON, AND MAURICIO TOHEN
During the past decade, the descriptive epidemiology of bipolar disorder (BD) has come to maturity. A proliferation of international studies has yielded aggregate lifetime prevalence rates of BD of 1-2% at the diagnostic level and 4-5% with expansion to the spectrum concept of bipolarity.1,2 BD was the second ranking cause of disability, measured by days spent out of role per year, among a range of physical and mental health conditions assessed in the World Health Organization World Mental Health surveys,3 and it is one of the leading causes of disability adjusted life years worldwide.4 Most strikingly, one in every four or five persons with BD has a history of suicide attempts.5 When taken together with the early age at onset and strong association with other mental disorders, these results provide further documentation of the individual and societal disability associated with this disorder.2 However, despite these advances in our understanding of BD at the general population level, the vast majority of global evidence on the prevalence, impact, and correlates of BD is based on cross-sectional research that cannot provide information on the course or outcome of BD, particularly at the milder end of the spectrum, that is critical for a comprehensive depiction of the public health significance of BD. Characterization of the lifetime course of BD may inform our understanding of causes, prevention, and treatment to minimize its individual and societal impact.
The goals of this chapter are (1) to provide a summary of the findings from studies of the course and mortality of BD from clinical and community samples and (2) to summarize methodological challenges and future directions in interpreting aggregate findings on the course of BD.