title: Irritable bowel syndrome and symptom severity: evidence of negative attention bias, diminished vigour, and autonomic dysregulation.
abstract: OBJECTIVE
  To determine if cognitive processing, and subjective and physiological responses to stress and relaxation differed between an irritable bowel syndrome (IBS) group and control group. How these variables relate to the severity of IBS symptoms was also determined.
  
  
  METHODS
  Twenty-one IBS participants and 20 controls provided cognitive (attention and processing), subjective (perceived stress and vigour), and physiological (heart rate, blood pressure, and skin conductance) data during a relaxation and stress phase. Logistic regression analyses determined which variables are related to the IBS group and hierarchical linear regression assessed how the variables are related to the severity of IBS symptoms.
  
  
  RESULTS
  Subjective and cognitive factors (drowsiness at baseline, total vigour, and reduced Stroop colour-naming accuracy for negative words) are significantly related to IBS, χ2 (3, N=41)=23.67, p<.001, accurately categorising 85% of participants. IBS symptom severity was associated with both subjective (drowsiness at baseline and a smaller reduction in tiredness from relaxation to stress) and physiological (smaller increase in systolic blood pressure from baseline to stress phase and lower skin conductance at baseline) variables. This model predicted IBS severity, F (4, 16)=11.20, p<.001, and accounted for 74% of the variability in scores.
  
  
  CONCLUSIONS
  A negative attention bias, which may be related to a negative self-schema, as well as perceived low vigour were important in categorising IBS. Low subjective vigour and reduced physiological reactivity to both relaxation and stress conditions were associated with IBS severity, suggestive of illness-related allostatic load.
authors.affiliation: School of Psychological Science, La Trobe University, Melbourne, Australia.
authors.forename: Kristy
authors.initials: K
authors.lastname: Phillips
authors.affiliation: School of Psychological Science, La Trobe University, Melbourne, Australia.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Wright
authors.affiliation: School of Psychological Science, La Trobe University, Melbourne, Australia. Electronic address: s.kent@latrobe.edu.au.
authors.forename: Stephen
authors.initials: S
authors.lastname: Kent
mesh_terms: D000328:Adult; D001288:Attention; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001794:Blood Pressure; D016022:Case-Control Studies; D005260:Female; D005712:Galvanic Skin Response; D006339:Heart Rate; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000503:physiopathology* / Q000523:psychology*; D008297:Male; D012894:Sleep Stages; D013315:Stress, Psychological; D057190:Stroop Test
keywords: Allostatic load; Blood pressure; Progressive muscle relaxation; Skin conductance; Stress; Stroop-test