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.