Original Article Behavioral Approach System and Behavioral Inhibition System sensitivities and bipolar

spectrum disorders: prospective prediction of bipolar mood episodes Bipolar disorder (BD) is often a severe, recurrent, or unremitting illness involving significant impair-ment in many areas of functioning, including erratic work performance and high rates of divorce and suicide (1, 2). During their lifetime, approxi-mately 1.5 % of the US population (3) and 0.5– 3.5 % of the world population (4) will experience BD and up to 5 % will experience a bipolar spec-trum condition (5). Research has provided support for a continuum or spectrum of severity within the bipolar category ranging from the milder, subsyn-dromal cyclothymia, to bipolar II disorder, to full-blown bipolar I disorder (2, 6–10). BD is the sixth leading cause of disability among both physical and psychiatric disorders worldwide (11); however