title: Reverse causality in the association between whiplash and symptoms of anxiety and depression: the HUNT study.
abstract: METHODS
  Longitudinal population-based cohort study.
  
  
  OBJECTIVE
  The aim of this study was to examine the possibility of reverse causality, that is, if symptoms of anxiety and depression are associated with incident self-reported whiplash injury. The clinical relevance of self-reported whiplash injury was evaluated by its association with subsequent disability pension award.
  
  
  BACKGROUND
  Whiplash is associated with an increased level of anxiety and depressive symptoms. This increase in psychological distress is generally understood as the consequence of the accident and related whiplash.
  
  
  METHODS
  Longitudinal data from the HUNT study was used. Baseline measures of symptoms of anxiety and depression were used in prediction of incident whiplash injury self-reported at follow-up 11 years later. Incident disability pension award was obtained from a comprehensive national registry during 2-year follow-up after self-reported whiplash injury.
  
  
  RESULTS
  Case-level symptom load of anxiety and depression at baseline increased the likelihood of reporting incident whiplash at follow-up (odds ratio [OR] = 1.60, 95% confidence interval = 1.22-2.11). Self-reported whiplash increased the chances of a subsequent disability pension award (OR = 6.54), even in the absence of neck pain (OR = 3.48).
  
  
  CONCLUSIONS
  This is the first published study with a prewhiplash prospective evaluation of psychological status. Our findings are in conflict with previous research suggesting whiplash to be the cause of associated psychological symptoms rather than their consequence. Self-reported whiplash injury was clinically relevant as it independently increased subsequent disability pension award. The strength of this effect, even in the absence of neck pain, suggests the ascertainment of this diagnostic label, or factors associated with this, are important predictors of disability.
authors.affiliation: Norwegian Institute of Public Health, Division of Mental Health, Oslo, Norway. arnstein.mykletun@uib.no
authors.forename: Arnstein
authors.initials: A
authors.lastname: Mykletun
authors.forename: Nicholas
authors.initials: N
authors.lastname: Glozier
authors.forename: Hanne Gro
authors.initials: HG
authors.lastname: Wenzel
authors.forename: Simon
authors.initials: S
authors.lastname: Overland
authors.forename: Samuel B
authors.initials: SB
authors.lastname: Harvey
authors.forename: Simon
authors.initials: S
authors.lastname: Wessely
authors.forename: Matthew
authors.initials: M
authors.lastname: Hotopf
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001007:Anxiety / Q000453:epidemiology* / Q000523:psychology*; D015984:Causality; D015331:Cohort Studies; D003863:Depression / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods; D011446:Prospective Studies; D057566:Self Report / Q000592:standards; D014911:Whiplash Injuries / Q000453:epidemiology / Q000523:psychology; D055815:Young Adult