Bipolar disorder can be a severe, relapsing mental illness, and it shares characteristics with both major depressive disorder and schizophrenia. Like depressive disorders, bipolar disorder features recurrent episodes of altered mood that interfere with cognition and functioning. Like schizophrenia, it is a chronic disorder that often contains psychotic episodes and similar pathological findings. However, in contrast to late-life depression and schizophrenia, information about late-life bipolar disorder is relatively scarce (Bauer et al. 2002; Charney et al. 2003; Depp et al. 2005; Unutzer and Bruce 2002). Even basic facts, such as how age may affect the development or expression of bipolar disorder, where older adults with bipolar disorder live or access their health care, or how late-life bipolar disorder may affect social support, have been relatively lightly studied. Further, answers to elementary questions regarding such issues as the prevalence of late-life bipolar disorder and the best treatment practices are unclear (Charney et al. 2003; Unutzer and Bruce 2002).