title: Clinical and evoked pain, personality traits, and emotional states: can familial confounding explain the associations?
abstract: OBJECTIVE
  Pain is a complex phenomenon influenced by context and person-specific factors. Affective dimensions of pain involve both enduring personality traits and fleeting emotional states. We examined how personality traits and emotional states are linked with clinical and evoked pain in a twin sample.
  
  
  METHODS
  99 female twin pairs were evaluated for clinical and evoked pain using the McGill Pain Questionnaire (MPQ) and dolorimetry, and completed the 120-item International Personality Item Pool (IPIP), the Positive and Negative Affect Scale (PANAS), and ratings of stress and mood. Using a co-twin control design we examined a) the relationship of personality traits and emotional states with clinical and evoked pain and b) whether genetics and common environment (i.e. familial factors) may account for the associations.
  
  
  RESULTS
  Neuroticism was associated with the sensory component of the MPQ; this relationship was not confounded by familial factors. None of the emotional state measures was associated with the MPQ. PANAS negative affect was associated with lower evoked pressure pain threshold and tolerance; these associations were confounded by familial factors. There were no associations between IPIP traits and evoked pain.
  
  
  CONCLUSIONS
  A relationship exists between neuroticism and clinical pain that is not confounded by familial factors. There is no similar relationship between negative emotional states and clinical pain. In contrast, the relationship between negative emotional states and evoked pain is strong while the relationship with enduring personality traits is weak. The relationship between negative emotional states and evoked pain appears to be non-causal and due to familial factors.
authors.affiliation: Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, WA.|University of Washington Twin Registry, University of Washington, Seattle, WA.
authors.forename: Eric
authors.initials: E
authors.lastname: Strachan
authors.affiliation: Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, WA.
authors.forename: Brian
authors.initials: B
authors.lastname: Poeschla
authors.affiliation: Department of Anesthesiology, University of Washington, Seattle, WA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Dansie
authors.affiliation: University of Washington Twin Registry, University of Washington, Seattle, WA.|Department of Medicine, University of Washington, Seattle, WA.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Succop
authors.affiliation: Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, WA.|University of Washington Twin Registry, University of Washington, Seattle, WA.
authors.forename: Laura
authors.initials: L
authors.lastname: Chopko
authors.affiliation: VA Center of Excellence for Stress and Mental Health, VA San Diego He althcare System, and Department of Psychiatry, University of California, San Diego, CA.|University of Washington Twin Registry, University of Washington, Seattle, WA.
authors.forename: Niloofar
authors.initials: N
authors.lastname: Afari
mesh_terms: D000328:Adult; D000339:Affect; D001008:Anxiety Disorders / Q000150:complications*; D004644:Emotions; D005260:Female; D006801:Humans; D008603:Mental Health; D000075384:Neuroticism; D010146:Pain / Q000503:physiopathology* / Q000523:psychology*; D010147:Pain Measurement; D010551:Personality; D010555:Personality Inventory; D013315:Stress, Psychological / Q000209:etiology; D014427:Twins / Q000523:psychology*
keywords: Clinical pain; Emotions; Evoked pain; Extraversion; Neuroticism; Personality; Twins