Greater Cognitive Decline in Individuals at Risk for Bipolar Disorder With Obesity

The burden of illness associated with bipolar disorder warrants early preemption.

Obesity leads to increased cognitive impairment in individuals at varying degrees of risk for bipolar disorder, according to a study published in Bipolar Disorders.

Since bipolar disorder warrants early preemption and prevention, Roger S. McIntyre, MD, of the department of psychiatry, University of Toronto, Ontario, Canada, and colleagues investigated the importance of evaluating medical comorbidities in bipolar disorder. The study builds on evidence suggesting that “noncommunicable, chronic, and life-threatening medical disorders (eg, obesity and cardiovascular disease) differentially affect individuals with bipolar disorder, and influence illness trajectory and progression.”

The researchers obtained data from the Recognition and Early Intervention on Prodromal Bipolar Disorders (REI-PBD) study, which seeks to validate the early stages preceding full-blown bipolar disorder and to evaluate the effectiveness of aerobic exercise as an early intervention in individuals at ultra high risk (UHR) for bipolar disorder. Participants between age 8 and 28 were recruited between March 2013 and October 2015; subjects with a positive family history of bipolar disorder were compared with controls who had a negative family history of bipolar disorder, and were then assessed using a 74-item checklist of observable symptoms.

The results of the analysis, which included 36 individuals at high risk for bipolar disorder, 33 individuals at UHR for bipolar disorder, and 48 age-matched controls, displayed multiple negative correlations with body mass index (BMI). There was a statistically significant negative association between BMI and performance on speed processing measures (r =−186, P =.047 according to the Brief Assessment of Cognition in Schizophrenia) and between BMI and attention/vigilance (r =−257, P =.006), according to the Continuous Performance Test-Identical Pairs.

There were also trends for negative correlations between BMI and working memory on the Wechsler Memory Scale-III Spatial Span (r =−.177; P =.059) and an overall cognition score (r =.157; P =.097, Measurement and Treatment Research to Improve Cognition in Schizophrenia). The effects of UHR status on the associations between BMI and cognitive functioning were also significant.

“Individuals who are at UHR for bipolar disorder, on the basis of well-established phenomenological and family history data, are more likely to exhibit decrements in cognitive performance as a function of increasing overweight status,” the researchers said. “Our findings herein, as well as the salutary effects of bariatric surgery on measures of cognitive function in obese populations, provide the rationale for hypothesizing that mitigating excess weight in individuals at elevated risk for bipolar disorder may forestall or prevent declaration of illness.”

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McIntyre RS, Mansur RB, Lee Y, et al. Adverse effects of obesity on cognitive functions in individuals at ultra high risk for bipolar disorder: Results from the global mood and brain science initiative [Published online May 11, 2017]. Bipolar Disord. doi:10.1111/bdi.12491.