Body Mass Index Predicts Decline in Executive Function in Bipolar Disorder: Preliminary Data of a 12-Month Follow-up Study

Introduction: Obesity and associated risk factors have been linked to cognitive decline before. Objectives: In the present study, we evaluated potential cumulative negative effects of overweight and obesity on cognitive performance in euthymic patients with bipolar disorder (BD) in a longitudinal design. Methods: Neurocognitive measures (California Verbal Learning Test, Trail Making Test [TMT] A/B, Digit-Symbol-Test, Digit-Span, d2 Test), anthropometrics (e.g., body mass index [BMI]), and clinical ratings (Hamilton Depression Scale, Young Mania Rating Scale) were collected over a 12-month observation period. Follow-up data of 38 patients with BD (mean age 40 years; 15 males, 23 females) were available. Results: High baseline BMI predicted a decrease in the patient's performance in the Digit-Span backwards task measuring working memory performance. In contrast, cognitive performance was not predicted by increases in BMI at follow-up. Normal weight bipolar patients (n = 19) improved their performance on the TMT B, measuring cognitive flexibility and executive functioning, within 1 year, while overweight bipolar patients (n = 19) showed no change in this task. Conclusions: The results suggest that overweight can predict cognitive performance changes over 12 months.

Automated summary

The study evaluated the potential negative effects of overweight and obesity on cognitive performance in euthymic patients with bipolar disorder over a 12-month period. It found that high baseline BMI predicted a decrease in working memory performance, while cognitive flexibility and executive functioning improved in normal weight patients but showed no change in overweight patients within 1 year. The results suggest that overweight can predict cognitive performance changes over time.