Cognitive flexibility: A trait of bipolar disorder that worsens with length of illness.

INTRODUCTION: Deficits in cognitive flexibility, a difficulty altering thoughts and behavioral responses in a changing environment, are found in individuals with bipolar disorder (BD) and are associated with poor social and work functioning. However, the current literature is inconsistent in clarifying the long-term nature of these deficits for those with BD. We administered a common task of cognitive flexibility, the Wisconsin Card Sorting Task (WCST) and accounted for demographics, clinical, and cognitive features of BD, to determine the state versus trait characteristics of these deficits.

METHOD: The Wisconsin Card Sorting Test (WCST) was administered to 154 adults with BD and 95 healthy controls twice, one year apart.

RESULTS: The main findings show that cognitive inflexibility is a trait feature of BD, independent of clinical features, that may modestly worsen over time due to the presence of certain demographic, cognitive, and functional features of the disorder. In addition, improvements in WCST performance over an extended period of time in both those with and those without already existing cognitive flexibility deficits indicate potential practice effects.

CONCLUSIONS: These findings suggest that the implementation of early interventions before the illness progresses could potentially prevent further cognitive impairment, mitigate functional outcomes, and improve the quality of life of the individual with BD.