Posted: 01.12.2014 | by AMRA
Patients with bipolar disorder display irregularities in their emotional processing even when they appear overtly asymptomatic. Howells et al. [Metabolic Brain Disease] explored the impact of MBCT on biological markers of emotional processing irregularities in a cohort of stably remitted bipolar patients. Prior to receiving MBCT, 12 bipolar patients in remission were compared with 9 healthy controls. Both groups underwent a monitoring process of electrical activity of the brain (electroencephalography; EEG) and heart (electrocardiography; ECG) while completing tasks involving matching inanimate objects, matching facial expressions, and labeling emotions.
The bipolar patients showed exaggerated negative event-related potentials (ERPs) on their EEGs at approximately 170 milliseconds after stimulus exposure (ERP N170) and higher heart rate variability high frequency (HRV-HF) peaks on their ECGs. Both differences were especially significant during the facial expression matching task, which may reflect impaired communication between the cerebral cortex and the amygdala during emotional processing. This functional impairment may limit the ability of bipolar patients to control their affective reactivity, rendering them vulnerable to relapse.
The bipolar patients were then retested after completing an 8-week MBCT program, and they showed significant reduction in their exaggerated ERP N170 responses and their elevated HRV-HF peaks compared to their initial baseline measures. There was no change in bipolar symptoms observed after MBCT, probably reflecting the fact that participants were in stable remission. While these results are supportive of MBCT’s promise in treating the emotional processing deficits of bipolar patients, caution is needed in interpreting results due to limitations in this pilot study, including its small sample size, lack of repeated measures for the control group, and the unknown effects of patient medication on the physiological measures assessed.
Howells, F. M., Rauch, H. G. L., Ives-Deliperi, V. L., Horn, N. R., & Stein, D. J. (2014). Mindfulness based cognitive therapy may improve emotional processing in bipolar disorder: Pilot ERP and HRV study. Metabolic Brain Disease, 29(2):367-75. [PMID: 2429483]