Journal of the International Neuropsychological Society

Processing efficiency and sustained attention in bipolar disorder

DAVID E.  FLECK  a1 c1 , PAULA K.  SHEAR  a1 a2 and STEPHEN M.  STRAKOWSKI  a1 a2
a1 Center for Bipolar Disorders Research, Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati
a2 Department of Psychology, University of Cincinnati, Cincinnati

Article author query
fleck de   [PubMed][Google Scholar] 
shear pk   [PubMed][Google Scholar] 
strakowski sm   [PubMed][Google Scholar] 


We hypothesized that patterns of sustained attention performance in bipolar disorder were consistent with processing efficiency theory—a theory of the relationship between central processing capacity and performance. We predicted (1) sustained attention deficits during mania because symptoms interfere with limited-capacity executive control processes resulting in decreased performance effectiveness; and (2) decreased processing efficiency during euthymia, as indicated by speed/accuracy tradeoffs, consistent with a stable phenotypic abnormality. Twenty-five manic bipolar, 23 euthymic bipolar, and 28 healthy comparison participants were compared on a continuous performance task and administered symptom-rating scales. The manic group was significantly impaired on overall perceptual sensitivity and demonstrated a significant linear decrease in performance over time, consistent with impaired sustained attention. The euthymic group evidenced significantly slower overall hit reaction time (RT), but when RT was controlled they performed similarly to the healthy group over time. Two discriminant functions combined to separate the groups on manic symptom severity and on-task effort/strategy use. These findings are consistent with processing efficiency theory. They suggest that euthymic patients sustain attention through effortful control at the expense of processing efficiency, while acute mania reduces the capacity for control and impairs sustained attention. Problems with processing efficiency are viewed as trait characteristics of bipolar disorder that may be overlooked by traditional error-based assessments. (JINS, 2005, 11, 49–57.)

(Received April 6 2004)
(Revised August 30 2004)
(Accepted August 31 2004)

Key Words: Bipolar disorder; Mania; Processing efficiency theory; Sustained attention; Continuous performance test.

c1 Reprint requests to: David E. Fleck, Ph.D., Department of Psychiatry, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0559. E-mail: