A multimethod investigation of the behavioral activation system in bipolar disorder.

Dysregulation in behavioral activation system (BAS) activity has been implicated in the pathogenesis of bipolar disorder (BPD). To characterize BAS activity and related facets in this disorder, the authors compared 59 participants with BPD to 44 controls on multiple measures of BAS activity, including a standardized behavioral task, self-reports, and electroencephalographic indexes of regional cortical activity. Levels of putative BAS activity differed depending on assessment strategy. When a behavioral task indexing reward sensitivity was used, euthymic BPD patients showed evidence of higher BAS activity than either control participants or patients who were in a mood episode. Following a mood induction procedure designed to elicit BAS activity, currently episodic patients showed relatively greater left anterior cortical activity than either euthymic or control participants. Implications of the findings for future research on BPD vulnerability are described.