Misalignments of rest-activity rhythms in inpatients with schizophrenia

Manami Kodaka, Satoshi Tanaka, Madoka Takahara, Atsuko Inamoto, Shuichiro Shirakawa, Masatoshi Inagaki, Nobumasa Kato, Mitsuhiko Yamada

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Aims: 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 χ2 periodogram to compute rest-activity rhythms from the activity data, whereby the χ2 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 χ2 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. Conclusion: Changes in rest-activity rhythms by optimizing pharmacological and non-pharmacological treatment could improve social adjustment or quality of life in patients with schizophrenia.

Original languageEnglish
Pages (from-to)88-94
Number of pages7
JournalPsychiatry and clinical neurosciences
Issue number1
Publication statusPublished - Feb 2010


  • Circadian rhythm
  • Diazepam
  • Inpatients
  • Schizophrenia
  • Social adjustment

ASJC Scopus subject areas

  • Neuroscience(all)
  • Neurology
  • Clinical Neurology
  • Psychiatry and Mental health


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