title: Distribution of Active and Resting Periods in the Motor Activity of Patients with Depression and Schizophrenia.
abstract: OBJECTIVE
  Alterations of activity are prominent features of the major functional psychiatric disorders. Motor activity patterns are characterized by bursts of activity separated by periods with inactivity. The purpose of the present study has been to analyze such active and inactive periods in patients with depression and schizophrenia.
  
  
  METHODS
  Actigraph registrations for 12 days from 24 patients with schizophrenia, 23 with depression and 29 healthy controls.
  
  
  RESULTS
  Patients with schizophrenia and depression have distinctly different profiles with regard to the characterization and distribution of active and inactive periods. The mean duration of active periods is lowest in the depressed patients, and the duration of inactive periods is highest in the patients with schizophrenia. For active periods the cumulative probability distribution, using lengths from 1 to 35 min, follows a straight line on a log-log plot, suggestive of a power law function, and a similar relationship is found for inactive periods, using lengths from 1 to 20 min. For both active and inactive periods the scaling exponent is higher in the depressed compared to the schizophrenic patients.
  
  
  CONCLUSIONS
  The present findings add to previously published results, with other mathematical methods, suggesting there are important differences in control systems regulating motor behavior in these two major groups of psychiatric disorders.
authors.affiliation: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.; Department of Clinical Medicine, Section for Psychiatry, University of Bergen, Bergen, Norway.; K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, Bergen, Norway.
authors.forename: Ole Bernt
authors.initials: OB
authors.lastname: Fasmer
authors.affiliation: Olaviken Psychiatric Hospital, Bergen, Norway.
authors.forename: Erik
authors.initials: E
authors.lastname: Hauge
authors.affiliation: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.
authors.forename: Jan Øystein
authors.initials: JØ
authors.lastname: Berle
authors.affiliation: Comprehensive Doctors Medical Group, Arcadia, CA, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Dilsaver
authors.affiliation: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.; Department of Clinical Medicine, Section for Psychiatry, University of Bergen, Bergen, Norway.; K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, Bergen, Norway.
authors.forename: Ketil J
authors.initials: KJ
authors.lastname: Oedegaard
keywords: Actigraphy; Depression; Motor activity; Schizophrenia