Impact of mood on endothelial function and arterial stiffness in bipolar disorder

Background: Previous research on bipolar disorder demonstrates greater-than-expected vascular dysfunction later in the course of illness, proportionate to the cumulative burden of mood symptoms. However, little is known about the effect of acute mood states on vascular function. Here, we examine the relation between vascular function and mood state in individuals with bipolar disorder. Materials and Methods: This prospective study followed forty individuals with bipolar disorder for up to 6 months. The participants were assessed for mood state and vascular function at baseline, 2 weeks, and 6 months. Mood state was determined using the clinician-administered Montgomery–Ssberg Depression Rating Scale and Young Mania Rating Scale. Vascular function was assessed by flow-mediated dilation (FMD) of the brachial artery, forearm vascular resistance (FVR), and arterial stiffness. Results: The participants had a mean age of 30.1 years, and 75% were male. Primary outcome measures such as FMD and nitroglycerine-mediated dilation were not found to have statistically significant associations with depressive or manic symptoms. In unadjusted models, higher manic symptoms were significantly associated with increased FVR nitroprusside-mediated dilation and diastolic blood pressure. In adjusted models, higher depressive symptoms were significantly associated with increases in augmentation index adjusted for heart rate of 75 bpm, and higher manic symptoms remained associated with increases in diastolic blood pressure. Conclusion: FMD may have limited sensitivity as a biomarker for measuring short-term effects of mood state. Long-term prospective studies are needed to clarify the temporal relation between chronic mood symptoms and vascular function in bipolar disorder.