Variations in Diurnal Rhythm Linked to Mood Variability in Bipolar Disorder

For patients with borderline personality disorder or bipolar disorder, variations in mood may be linked to variations in diurnal rhythm caused by activity, sleep, and heart rate, according to findings published in Scientific Reports. These results suggest that improving the regularity of sleep may be an effective therapy for both bipolar disorder and borderline personality disorder.

The study included participants with bipolar disorder (n=20), participants with borderline personality disorder (n=14), and healthy controls (n=20).

A Mood Zoom smartphone application prompted participants to provide their mood 10 times per day at evenly spaced intervals. A Proteus patch monitored heart rate and acceleration in the participants, which the researchers used for a long-term analysis of diurnal patterns in physiologic and behavioral measures.

The results of the Mood Zoom questionnaires indicated that participants with borderline personality disorder had greater variability in negative mood compared with participants with bipolar disorder. Participants with bipolar disorder had greater variability in negative mood compared with controls.

Participants with borderline personality disorder had greater variability in sleep phase and amplitude compared with participants with bipolar disorder and controls. Participants with bipolar disorder also had greater variability in sleep phase and amplitude compared with controls.

When the researchers calculated correlations, they found that the variability of sleep phases had high positive correlations with variability of all mood dimensions in both borderline personality disorder and bipolar disorder.

The researchers found several other patterns of correlation in borderline personality disorder. Negative mood variability was highly correlated with a measure of variability of sleep timings. Variation in signal amplitude was strongly positively correlated with measures of emotion. These correlations were not seen in patients with bipolar disorder or in controls.

“The results suggest that variable diurnal function is more characteristic of the [borderline personality disorder] than the [bipolar disorder] phenotype and so treatment efforts might be explored which would regularize circadian function as a way to regulate abnormal mood in [borderline personality disorder],” the researchers wrote.

Addressing sleep regularity in patients with bipolar disorder and borderline personality disorder may potentially improve quality of life in these patients.

Reference

Carr O, Saunders KEA, Tsanas A, et al. Variability in phase and amplitude of diurnal rhythms is related to variation of mood in bipolar and borderline personality disorder. Sci Rep. 2018;8:1649.