Desynchronization of diurnal rhythms in bipolar disorder and borderline personality disorder

Abstract

It has long been proposed that diurnal rhythms are disturbed in bipolar disorder (BD). Such changes are obvious in episodes of mania or depression. However, detailed study of patients between episodes has been rare and comparison with other psychiatric disorders rarer still. Our hypothesis was that evidence for desynchronization of diurnal rhythms would be evident in BD and that we could test the specificity of any effect by studying borderline personality disorder (BPD). Individuals with BD (n = 36), BPD (n = 22) and healthy volunteers (HC, n = 25) wore a portable heart rate and actigraphy device and used a smart-phone to record self-assessed mood scores 10 times per day for 1 week. Average diurnal patterns of heart rate (HR), activity and sleep were compared within and across groups. Desynchronization in the phase of diurnal rhythms of HR compared with activity were found in BPD (+3 h) and BD (+1 h), but not in HC. A clear diurnal pattern for positive mood was found in all subject groups. The coherence between negative and irritable mood and HR showed a four-cycle per day component in BD and BPD, which was not present in HC. The findings highlight marked de-synchronisation of measured diurnal function in both BD but particularly BPD and suggest an increased association with negative and irritable mood at ultradian frequencies. These findings enhance our understanding of the underlying physiological changes associated with BPD and BD, and suggest objective markers for monitoring and potential treatment targets. Improved mood stabilisation is a translational objective for management of both patient groups.

Fig. 1. An example of data recorded from the Proteus patch for one participant.

a total acceleration, b integrated total acceleration with daily sinusoid fits, c vertical acceleration, d integrated vertical acceleration with daily sinusoid fits, and e HR with daily sinusoid fits

Fig. 2. Average sinusoids of sleep, HR and activity shown for two days for each subject.

Statistically significant differences (p < 0.05) between the phase of each pair of sinusoids, testing if the mean differs from zero, are marked with an asterisk. A significant difference suggests there is a phase lag between the two measures

Fig. 3

Diurnal patterns (over two days) for each subject group of the average score for the first three principal components of MZ, a negative, b positive and c irritable, repeated over a 48 h period. Solid line represents the mean score, with the dashed period representing the times where no MZ recordings are made. Shaded regions show the standard deviation divided by the square root of group size

Fig. 4

Coherence between total acceleration, sleep and HR signals with negative, positive and irritable MZ scores for: a BD and HC participants, and b BPD and HC participants. The shaded black bars indicate frequencies at which statistically significant differences between groups were found