The Visceral Sensitivity Index: Development and Validation of a Gastrointestinal Symptom-Specific Anxiety Scale

J. S. Labus; R. Bolus; L. Chang; I. Wiklund; J. Naesdal; E. A. Mayer; B. D. Naliboff

Disclosures

Aliment Pharmacol Ther. 2004;20(1) 

In This Article

Summary and Introduction

Background: Anxiety related to gastrointestinal sensations, symptoms or the contexts in which these may occur is thought to play a significant role in the pathophysiology as well as in the health outcomes of patients with irritable bowel syndrome.
Aim: To develop a valid and reliable psychometric instrument that measures gastrointestinal symptom-specific anxiety.
Methods: External and internal expert panels as well as a patient focus group evaluated a large pool of potential item stems gathered from the psychological and gastrointestinal literature. Potential scale items were then administered to 96 patients diagnosed with irritable bowel syndrome along with a set of validating questionnaires. Final item selection was based upon rigorous empirical criteria and the psychometric properties of the final scale were examined.
Results: A final unidimensional 15-item scale, the Visceral Sensitivity Index, demonstrated excellent reliability as well as good content, convergent, divergent and predictive validity.
Conclusions: The findings suggest that the Visceral Sensitivity Index is a reliable, valid measure of gastrointestinal symptom-specific anxiety that may be useful for clinical assessment, treatment outcome studies, and mechanistic studies of the role of symptom-related anxiety in patients with irritable bowel syndrome.

Irritable bowel syndrome (IBS) is characterized by chronic abdominal pain or discomfort associated with altered bowel habits. It is the most common of the functional gastrointestinal (GI) disorders (10-15% prevalence)[1] and has an impact on disease-related quality of life (QoL) comparable with that of depression and chronic renal failure.[2] Converging clinical, epidemiological and experimental evidence is consistent with a pathophysiological model of IBS that is multifactorial and includes a prominent role for altered central stress responses. This evidence includes the association of IBS symptom exacerbations with certain stressful[3,4,5] or traumatic[6] life events, frequently reported comorbidity with anxiety disorders, in particular panic disorder and post-traumatic stress disorder,[7] and efficacy of pharmacological and non-pharmacological treatments targeted at the stress circuitry of the central nervous system (CNS).[8,9]

While peripheral changes in the gut may contribute to overall IBS symptoms in some patients, an altered sensitivity or responsiveness of the emotional motor system (EMS) has been proposed to play an important role in the mediation of autonomic and neuroendocrine responses, as well as pain modulation in response to stressful life events.[10] It has previously been suggested that GI symptom-specific anxiety (GSA) may be an important endogenous stressor perpetuating IBS symptoms, even in the absence of external stressors.[11] Similar models of symptom-related anxiety have been shown to play an important role in symptom maintenance and treatment response in other syndromes including chronic pain and panic disorder.[12,13,14] Most importantly, pathological anxiety directed towards bodily sensations may be present even in patients who do not meet DSM-IV criteria for anxiety disorders.[15,16] Thus, while IBS patients generally are found to have psychiatric comorbidity in the form of anxiety disorders of up to 40%,[9] a much larger number may show GSA, making the overall prevalence of all types of anxiety in these patients much higher.

In addition to playing a possible role in the pathophysiology of IBS, GSA may play a role in the unexpected severe impairment of disease-related QoL reported by these patients.[2,17] A recent analysis of specific factors contributing to the QoL impairment in IBS patients found worries about symptoms to be a highly significant predictor of QoL impairment.[17]

Finally, symptom-related anxiety may respond particularly well to therapies such as anxiolytics, 5-HT3 receptor antagonists, and other centrally targeted compounds such as corticotropin-releasing factor receptor and neurokinin-1 receptor antagonists, as well as various cognitive behavioural therapies. A reduction of this anxiety may play an important role in improving global end-points commonly used in IBS trials, and these global end-points, as well as QoL measures may be greatly influenced by a reduction in symptom-related anxiety. In the current study, a measure of GSA is developed and support for the psychometric properties of this instrument is provided.

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