Study participants rated their cognitive abilities significantly lower than their test scores, underscoring an important avenue for therapeutic intervention.
With a roller coaster of manic highs and heart-wrenching lows that can often involve negative self-perceptions, bipolar disorder can have a devastating impact on patients and their families. In their recent study, Vancouver Coastal Health Research Institute researchers Drs. Ivan Torres and Lakshmi Yatham found that subjective and objective tests of the cognitive abilities of people with bipolar disorder could represent a substantial therapeutic opportunity.
“To date, bipolar disorder research into cognition has mostly been concerned with how well people with bipolar disorder perform on objective cognitive tests,” says Torres. “The second wave of bipolar disorder research, which we discuss in this study, probes deeper: exploring how individuals with bipolar appraise their own cognitive abilities on top of objective cognitive test results.”
"We found that there is a significant mismatch between subjective views of cognitive abilities and the results of objective cognitive performance tests among the people with bipolar disorder who participated in our study.”
Published in the Journal of the International Neuropsychological Society, Torres and Yatham’s study not only looked at how participants felt about their cognitive abilities, they also tested two distinct categories of cognitive function: crystallized and fluid. Crystallized cognitive skills are those such as vocabulary and verbal knowledge, whereas fluid cognitive abilities include memory, executive function and information processing speed.
Typically, bipolar disorder — which is now understood to be a brain disorder — results in more fluid ability impairments, leaving crystallized cognitive abilities relatively intact.
Research findings are promising but larger cohort studies are needed
For Torres and Yatham’s study, 80 individuals with bipolar disorder and 55 healthy community controls completed several objective and subjective cognitive tests, with some objective tests geared towards testing crystallized cognitive abilities and others towards testing fluid cognitive abilities.
The results surprised the research team. They found that both participants and healthy controls had similarly intact crystallized and fluid cognitive skills. However, when it came to participants’ subjective ratings of their cognitive abilities, the test group rated themselves significantly lower than the control group.
“There was a large difference between how people with bipolar disorder performed on the cognitive tests and how they rated their cognitive difficulties in everyday life.”
“The effect sizes showed that people with bipolar rated their cognitive abilities four to five times lower than the controls,” says Torres. “This was despite the fact that all participants’ crystallized and fluid skills were mostly the same.”
“What we see is an overly negative self-perception of cognition among people with bipolar disorder that is out of sync with objective test scores of these abilities,” says Yatham. “An area for further research is to investigate to what extent this negative self-perception of cognition could be harming people with bipolar disorder and whether therapeutic interventions aimed at addressing this mismatch could improve patients’ self-judgments and moods.”
A potential intervention could be for clinicians to ask their patients with bipolar disorder to take objective and subjective cognitive tests and then discuss the results together. Since negative cognitive self-image can contribute to worsening symptoms of depression, concrete examples that counter false commonly held beliefs among people with bipolar disorder may be beneficial.
“If there is a big discrepancy between how a person with bipolar disorder feels about their cognitive abilities and their actual cognitive performance, showing them that they are underestimating their abilities could support improved self-perception,” adds Torres. “Test results could offer a visual aid for discussing patients’ feelings, with potential benefits for an improved overall sense of well-being and quality of life.”
While participants in the study all performed similarly on both the crystallized and fluid cognitive tests, these results do not necessarily reflect the broader bipolar disorder community, Torres cautions.
“We know from existing research that bipolar disorder is often associated with impaired fluid cognitive performance,” Torres shares. “The people with bipolar disorder who participated in our study were more educated than average, which may account for their relatively high performance on the fluid cognitive skills tests.”
“Additional research that is more representative of the variance in levels of education and other demographic characteristics found in the broader population is needed to deepen our understanding of the potential discrepancies between objective and subjective cognitive test results among people with bipolar disorder.”
