title: Relationship between psychosomatic complaints and circadian rhythm irregularity assessed by salivary levels of melatonin and growth hormone.
abstract: BACKGROUND
  In university health care settings, students with psychosomatic complaints often have chronotypic problems. For this reason, we investigated a potential connection between psychosomatic complaints and circadian rhythm irregularity assessed by salivary levels of melatonin and growth hormone.
  
  
  METHODS
  Fifteen healthy students between 21 and 22 years of age were examined for physiological parameters of chronotypes based on melatonin and growth hormone secretion patterns, using a fluorescence enzyme immunoassay. Salivary samples were collected from subjects at home five times each day (20:00, 24:00, 04:00, 08:00, and 12:00 h). In addition, the subjects rated their psychosomatic symptoms twice (at 08:00 and 20:00 h).
  
  
  RESULTS
  A group with irregular circadian rhythm of melatonin (ICR) showed more psychosomatic complaints than a group with the regular circadian rhythm (RCR), especially for anxiety.
  
  
  CONCLUSIONS
  Psychosomatic symptoms, particularly anxiety, may be associated with irregularity in melatonin and growth hormone rhythms, which can be altered by basic lifestyle habits even in healthy students.
authors.affiliation: Department of Educational Physiology, Faculty of Education, Chiba University, Japan. nagane@faculty.chiba-u.jp.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Nagane
authors.forename: Rie
authors.initials: R
authors.lastname: Suge
authors.forename: Shu-Ichi
authors.initials: S
authors.lastname: Watanabe