The behavioral activation system and mania.

For over two decades, theorists have suggested that mania relates to heightened sensitivity of the behavioral activation system (BAS). In this article, we review a burgeoning empirical literature on this model, drawing on both cross-sectional and prospective studies. As evidence has emerged for this model, we argue that it is time to consider more specific aspects of BAS sensitivity in this disorder. We review evidence that bipolar disorder relates to an increased willingness to expend effort toward reward and to increases in energy and goal pursuit after an initial reward. We conclude by considering the strengths and weaknesses of this literature, with an eye toward future directions and implications for treatment.