ABSTRACT
Bipolar disorder is characterized by recurrent manic and/or depressive episodes. It affects approximately 5.7 million (2.6%) American adults and causes severe impairments in functioning (Kessler, Chiu, Demler, Merikangas, & Walters, 2005; US Census Bureau, 2005). Hypomania/mania refers to a period of elevated, expansive, or irritable mood associated with inflated self-esteem, decreased need for sleep, being more talkative, flight of ideas or racing thoughts, increased distractibility, and increased goal directed behaviors often involving risky activities (e.g., excessive spending of money; American Psychiatric Association, 2013). Mania is diagnosed when the period of mood elevation lasts at least a week and is associated with functional impairment, whereas hypomanic episodes can be shorter (at least four days) and do not necessarily cause functional impairment (American Psychiatric Association, 2013). The traditional and widely accepted view of bipolar disorder is that of an illness that is characterized by time-limited acute episodes of hypomania, mania, and most often major depression interspersed with periods of symptomatic recovery associated with favorable functional outcomes (Trede et al., 2005). Mood-stabilizing medications are considered the first line of treatment for patients with bipolar disorder, although these treatments fail to bring many patients to sustained symptomatic and functional remission (Judd et al., 1998a, 1998b; Judd, Akiskal et al., 2003; Judd et al., 2002; Judd, Schettler et al., 2003; Perlis et al., 2006). In recent years, it has become increasingly clear that bipolar disorder, similar to schizophrenia, is a condition that for many patients is severely debilitating and worsens with the duration of the illness (Kessing, Andersen, & Mortensen, 1998; Rosa et al., 2012; Roy-Byrne, Post, Uhde, Porcu, & Davis, 1985). Neuroimaging studies in bipolar disorder have revealed functional abnormalities in brain regions involved in emotional and cognitive functioning. Neuropsychological studies in bipolar disorder not only have documented cognitive disturbances during mood episodes but show performance decrements in attention, memory, and executive functioning when patients are euthymic (i.e., neither depressed nor manic).
