Daily rest-activity patterns in the bipolar phenotype: A controlled actigraphy study

Abstract

This study assessed daily rest-activity patterns in euthymic, medication-naïve bipolar phenotype individuals. The Mood Disorder Questionnaire was used to identify 19 bipolar phenotype individuals and 21 controls. Participants wore an Actiwatch-L for 2 weeks to assess their sleep behaviour and circadian rest-activity rhythmicity. Bipolar phenotype individuals had increased movement during sleep, as assessed by the fragmentation index, greater activity levels during their least active 5 h (2 am–7 am), and lower circadian relative amplitude compared to controls. Higher activity levels during sleep affecting circadian amplitude in young adults with the bipolar phenotype may be associated with vulnerability for developing mood disorder.

• Bipolar phenotype
• circadian rhythm
• mood disorder
• relative amplitude of rest-activity
• sleep

Acknowledgments

This work was partly funded by a Medical Research Council PhD Studentship (P. L. R.) and the NIHR University of Oxford Biomedical Research Centre (K. W.).

Declaration of interests

PLR, GMG, CJH and KW do not have any conflicts of interest relating to the subject matter of this article. PLR is a full-time employee of Cambridge Cognition.