title: A system of chronic pain: disability consequential to accidental injury.
abstract: OBJECTIVE
  The aim of this research is to see if system theory is a tool that can give a new understanding of chronic pain.
  
  
  METHODS
  Over a 2-year period, a group of people with chronic pain was tested with measures of pain and the associated processes of depression, state and trait anxiety, sleep, and stress.
  
  
  RESULTS
  In the analysis, 'fear' emerged as a correlate of pain and a 'pain factor' was identified which comprised measures of pain, fear, and sleep. This factor could account for the disability associated with chronic pain, which is costly to the individual and society.
  
  
  CONCLUSIONS
  This study showed the validity of describing chronic pain as a system that could be understood using measures of pain, fear, and sleep. As a consequence, a set of commonly used terms is defined objectively and questions posed in the literature are answered.
authors: Department of Anatomy and Structural Biology, University of Otago, PO Box 56, Dunedin, New Zealand. mhmoon@es.co.nz
authors: Margaret H
authors: MH
authors: Moon
authors: Brian E
authors: BE
authors: Niven
mesh_terms: D001007:Anxiety / Q000209:etiology / Q000523:psychology; D002908:Chronic Disease; D003863:Depression / Q000209:etiology / Q000523:psychology; D005500:Follow-Up Studies; D006801:Humans; D008962:Models, Theoretical; D010146:Pain / Q000150:complications / Q000175:diagnosis*; D010147:Pain Measurement / Q000379:methods*; D011379:Prognosis; D011788:Quality of Life; D012984:Software; D011795:Surveys and Questionnaires