Variability of activity patterns across mood disorders and time of day

Karoline Krane-Gartiser,Jan Scott,Ole Bernt Fasmer,Kjetil Sørensen,Gunnar Morken,Arne E Vaaler

doi:10.1186/s12888-017-1574-x

Abstract

BackgroundFew actigraphy studies in mood disorders have simultaneously included unipolar (UP) and bipolar (BD) depression or BD mixed states as a separate subgroup from mania. This study compared objectively measured activity in UP, BD depression, mania and mixed states and examined if patterns differed according to time of day and/or diagnostic group.MethodsEighty -eight acutely admitted inpatients with mood disorders (52 UP; 18 mania; 12 BD depression; 6 mixed states) underwent 24 hours of actigraphy monitoring. Non-parametric analyses were used to compare median activity level over 24 h (counts per minute), two time series (64-min periods of continuous motor activity) in the morning and evening, and variability in activity across and within groups.ResultsThere was no between-group difference in 24-h median level of activity, but significant differences emerged between BD depression compared to mania in the active morning period, and between UP and mania and mixed states in the active evening period. Within-group analyses revealed that UP cases showed several significant changes between morning and evening activity, with fewer changes in the BD groups.ConclusionsMean activity over 24 hours has limited utility in differentiating UP and BD. In contrast, analysis of non-linear variability measures of activity at different times of day could help objectively distinguish between mood disorder subgroups.Trial registrationClinicalTrials.gov Identifier: NCT01415323, first registration July 6, 2011.

Highlights

Few actigraphy studies in mood disorders have simultaneously included unipolar (UP) and bipolar (BD) depression or bipolar disorders (BD) mixed states as a separate subgroup from mania
The analysis of the active morning period did not reveal any significant differences in median level or minute-to-minute variability in activity according to diagnostic subgroups
In the evening period pairwise comparisons revealed that cases in a mixed state had significantly higher levels of activity in the evening than UP cases (p = 0.019), but the overall between-group analysis of median activity count did not demonstrate any significant differences (Kruskal-Wallis test, p = 0.068)

Summary

Introduction

Few actigraphy studies in mood disorders have simultaneously included unipolar (UP) and bipolar (BD) depression or BD mixed states as a separate subgroup from mania. Actigraphy has been used to assess sleep profiles in bipolar disorders (BD) [3, 4], but there has been a shift in attention towards an examination of daytime activity and the 24-h rest-activity cycle in unipolar depression (UP) and BD [5, 6]. This change in focus coincides with the modification of diagnostic criteria for BD. Few studies have compared UP and BD groups that were recruited at the same time and/or from the same setting [13,14,15,16,17]

Methods

Results

Discussion

Conclusion