Pattern-Specific Brain Activation and Personalities Seen in Irritable Bowel Syndrome

May 22, 2003

May 21, 2003 (Orlando) — Patterns of brain activation in patients with irritable bowel syndrome (IBS) suggest an altered perception of pain compared with healthy subjects. Patients with IBS also tend to exhibit a distinct personality profile, which varies according to sex. Research demonstrating these findings were presented here during Digestive Disease Week 2003.

Stress is a major trigger for symptom flares in IBS, and how an individual copes with stress may influence disease status. Jeffrey M. Lackner, PsyD, from the Behavioral Medicine Clinic at the University at Buffalo School of Medicine in New York, reported that submissive, unassertive, introverted personalities predominate among patients with IBS.

Dr. Lackner and colleagues set out to identify personality types in 135 patients with IBS. Of these, 113 were women and 35 were men. Mean age was 49.4 years and duration of IBS was approximately 16 years.

The investigators scored patients on the 64-item Inventory of Interpersonal Problems (IIP, Alden, Wiggins and Pincus, 1990) and categorized patients according to the Interpersonal Circumplex, which organizes behavior into two major categories: (1) affiliation, which ranges from hostility to friendliness, and (2) dominance, which ranges from submissiveness to controlling.

Dr. Lackner reported that women with IBS tend to have traits of nonassertiveness and submissiveness. Men tend to be overaccommodating and have difficulty feeling and expressing anger, "like they are walking on eggshells," he said.

"With behavior modification, about 70% of patients with IBS are able to reduce their symptoms by 50% or more," Dr. Lackner said In an interview with Medscape. "When looked at in terms of the benefits of pharmacologic treatment, that's pretty impressive."

In a separate study, IBS patients showed different patterns of brain activation on gastrointestinal distention compared with healthy controls, reported Bruce D. Naliboff, PsyD, from the CNS Center for Neurovisceral Science and Female Health at the University of California in Los Angeles (UCLA).

Dr. Naliboff showed positron emission tomography (PET) images of the brains of 12 IBS patients — 10 men and 2 women — with a mean age of 39 years. He compared these with images taken of the brains of 12 healthy controls, also 10 men and 2 women. PET scans were taken at rest and after inflation of a balloon placed in the subjects' rectums.

IBS patients reported a higher level of discomfort or pain on balloon inflation than controls. PET scans of IBS patients showed activation in the hypothalamus, the anterior cingulate cortex and the dorsolateral prefrontal cortex while controls showed activation in the dorsal pons/PAG, which is a pontine pain inhibition area.

"IBS patients show more activation in areas that control cognition and evaluation of visceral sensation. They may have possible deficits in pain inhibition," Dr. Nabiloff said.

Management of these patients should include education about the illness, the UCLA psychologist said. "And at this point, we're still trying to figure out what IBS is.... It is important to give patients a positive model, of something they can do something about."

Dr. Lackner added that "cognitive behavioral therapy helps these patients process information differently. These patients show negativity, jump to conclusions, blow things out of proportion. Those behaviors make symptoms worse. They need to unlearn that style of thinking."

DDW 2003: Abstracts T1434, presented May 20, 2003; Abstract W1446, presented May 21, 2003.

Reviewed by Gary D. Vogin, MD

Martha Kerr is a freelance writer for Medscape.

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