title: Daily Actigraphy Profiles Distinguish Depressive and Interepisode States in Bipolar Disorder.
abstract: Disruptions in activity are core features of mood states in bipolar disorder (BD). This study sought to identify activity patterns that discriminate between mood states in BD. Locomotor activity was collected using actigraphy for six weeks in participants with inter-episode BD type I (n=37) or participants with no lifetime mood disorders (n=39). The 24-hour activity pattern of each participant-day was characterized and within-person differences in activity patterns were examined across mood states. Results show that among participants with BD, depressive days are distinguished from other mood states by an overall lower activity level, and a pattern of later activity onset, a midday elevation of activity, and low evening activity. No distinct within-person activity patterns were found for hypomanic/manic days. Since activity can be monitored non-invasively for extended time periods, activity pattern identification may be leveraged to detect mood states in BD, thereby providing more immediate delivery of care.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine.
authors.forename: Anda
authors.initials: A
authors.lastname: Gershon
authors.affiliation: Department of Human Development and Family Studies, The Pennsylvania State University.
authors.forename: Nilam
authors.initials: N
authors.lastname: Ram
authors.affiliation: Department of Psychology, University of California, Berkeley.
authors.forename: Sheri L
authors.initials: SL
authors.lastname: Johnson
authors.affiliation: Department of Psychology, University of California, Berkeley.
authors.forename: Allison G
authors.initials: AG
authors.lastname: Harvey
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine; Mental Illness Research Education and Clinical Center, VA Palo Alto Health Care System.
authors.forename: Jamie M
authors.initials: JM
authors.lastname: Zeitzer
keywords: Bipolar disorder; actigraphy; activity; circadian rhythms; depression