April 28, 2016

Similar Trajectory of Executive Functioning Performance over 5 years among individuals with Bipolar Disorder and Unaffected Controls using Latent Growth Modeling

Published in Journal of Affective Disorders

Cognitive impairment is fairly common in patients with bipolar disorder. The most notable impairments are in the areas of attention, verbal learning, emotion perception, and executive functioning. Executive functioning, or our ability to shift thinking, organize, plan, and solve problems, appears to be a chronic and persistent feature of bipolar disorder, but little is known regarding the stability of performance over time and by course of illness. This is of particular importance as deficits in executive functioning play a significant role in daily functioning and disability as well as quality of life. Further, it is unclear if cognitive change in bipolar disorder is progressive, meaning that there are progressive declines as patients get older or as they experience more mood episodes.

Researchers from the Heinz C. Prechter Bipolar Research Fund examined the natural course of executive functioning over a five year period among individuals with bipolar disorder and compared the natural course to those without any psychiatric illness. They used a strong analytical statistical approach that offers many advantages over traditional methods for longitudinal analyses. They found that those with bipolar disorder performed significantly worse on all executive functioning tasks compared to the control group, consistent with what we already know about the disorder. Most importantly, they found that changes in performance over five years were similar across both groups. Only being of older age was associated with greater decline in two executive functioning areas that involve processing speed.

The researchers conclude that there are persistent executive functioning deficits in patients with bipolar disorder, but the rate of change in performance over time is affected by age, similar to what we find in those with no psychiatric illness. These findings are striking in that having bipolar disorder does not accelerate executive functioning decline over time, arguing against a neuroprogressive disorder.

Summary provided by principal author Kelly Ryan, Ph.D.