title: Misalignments of rest-activity rhythms in inpatients with schizophrenia.
abstract: OBJECTIVE
  Rest-activity rhythms of human beings generally synchronize to a 24-h time cue. Very few detailed research studies have examined rest-activity rhythms in patients with schizophrenia. The present study aimed to explore (i) rest-activity rhythms in patients with schizophrenia, and (ii) factors relevant to their rhythm characteristics.
  
  
  METHODS
  We selected only inpatients for this research, because the time cue for inpatients was considered more standardized than that of outpatients. Sixteen inpatients with schizophrenia wore an ActiTrac accelerometer-based activity monitor (IM Systems Inc., Baltimore, USA) for eight consecutive days to measure their activity. We used a chi(2) periodogram to compute rest-activity rhythms from the activity data, whereby the chi(2) value amplitude was regarded as an index of regularity. We conducted non-parametric tests to identify factors relevant to rhythm cycles and patterns.
  
  
  RESULTS
  Half of the participants exhibited prolonged rest-activity cycles, and 25% also had irregular rest-activity patterns defined by insufficient chi(2) value amplitude, even though they were clearly under a 24-h time cue. Participants with misaligned rest-activity rhythms had attended daytime non-medical treatment programs less frequently, and had received more anti-anxiety/hypnotic medications than those with proper rhythms.
  
  
  CONCLUSIONS
  Changes in rest-activity rhythms by optimizing pharmacological and non-pharmacological treatment could improve social adjustment or quality of life in patients with schizophrenia.
authors.affiliation: Department of Psychogeriatrics, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan. mkodaka@ncnp.go.jp
authors.forename: Manami
authors.initials: M
authors.lastname: Kodaka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tanaka
authors.forename: Madoka
authors.initials: M
authors.lastname: Takahara
authors.forename: Atsuko
authors.initials: A
authors.lastname: Inamoto
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Shirakawa
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Inagaki
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Kato
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Yamada
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D002908:Chronic Disease; D015331:Cohort Studies; D003463:Cues; D003627:Data Interpretation, Statistical; D004780:Environment, Controlled; D005260:Female; D006801:Humans; D007297:Inpatients; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D011569:Psychiatric Status Rating Scales; D012146:Rest / Q000502:physiology*; D012559:Schizophrenia / Q000188:drug therapy / Q000453:epidemiology; D012565:Schizophrenic Psychology; D012959:Socioeconomic Factors; D013998:Time Perception
chemical_list: D014150:Antipsychotic Agents