title: Differences in psychomotor activity in patients suffering from unipolar and bipolar affective disorder in the remitted or mild/moderate depressive state.
abstract: BACKGROUND
  Abnormalities in psychomotor activity are a central and essential feature of affective disorder. Studies measuring differences in psychomotor activity between unipolar and bipolar disorder show divergent results and none have used a combined heart rate and movement monitor for measuring activity during free-living conditions.
  
  
  OBJECTIVE
  To compare objectively measured psychomotor activity in patients with unipolar and bipolar disorder in a remitted or mild/moderate depressive state. Further, both groups were compared to a healthy control group.
  
  
  METHODS
  A cross-sectional study of outpatients suffering from unipolar (n=20) and bipolar (n=18) disorder and healthy controls (n=31), aged 18-60 years. For three consecutive days a combined acceleration (m/s(2)) and heart rate (beats per minute) monitoring was used in conjunction with a step test to estimate activity energy expenditure (J/min/kg) as measures of psychomotor activity and physical fitness.
  
  
  RESULTS
  Overall score on Hamilton-17 items ranged between 0 and 22. Patients had higher sleeping heart rate (p<0.001), lower fitness (p=0.02), lower acceleration (p=0.004), and lower activity energy expenditure (p=0.004) compared to controls. Comparing unipolar and bipolar patients and adjusting for differences in Hamilton-17 revealed lower acceleration (p=0.01) and activity energy expenditure in bipolar patients (p=0.02); the difference was most prominent in the morning.
  
  
  CONCLUSIONS
  Electronic monitoring of psychomotor activity may be a promising additional tool in the distinction between unipolar and bipolar affective disorder when patients present in a remitted or depressive state.
authors.affiliation: The Copenhagen Affective Disorder Clinic, Psychiatric Centre Copenhagen, Rigshospitalet, Denmark.
authors.forename: Maria
authors.initials: M
authors.lastname: Faurholt-Jepsen
authors.forename: Søren
authors.initials: S
authors.lastname: Brage
authors.forename: Maj
authors.initials: M
authors.lastname: Vinberg
authors.forename: Ellen Margrethe
authors.initials: EM
authors.lastname: Christensen
authors.forename: Ulla
authors.initials: U
authors.lastname: Knorr
authors.forename: Hans Mørch
authors.initials: HM
authors.lastname: Jensen
authors.forename: Lars Vedel
authors.initials: LV
authors.lastname: Kessing
mesh_terms: D000293:Adolescent; D000328:Adult; D001714:Bipolar Disorder / Q000503:physiopathology / Q000523:psychology*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003718:Denmark; D003866:Depressive Disorder / Q000503:physiopathology / Q000523:psychology*; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance / Q000502:physiology*; D013315:Stress, Psychological / Q000503:physiopathology; D055815:Young Adult