| Purpose: |
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Individuals with irritable bowel syndrome (IBS) may experience abdominal pain as a result of
pain signals in the bowel and how these signals are processed in the brain. Studies using
brain imaging (pictures) have shown that IBS patients with more pain diagnoses (i.e.
fibromyalgia, migraines, etc.) have greater activity in the regions of the brain responsible
for the emotional and thought processing of pain signals. This could possibly make bowel
sensations and bowel difficulties feel abnormal or more noticeable, in turn causing more
severe IBS symptoms. The purpose of this protocol is to explore the role of pain diagnoses
and their affect on brain activity in IBS patients. The investigators will also examine the
use of a medication, desipramine, which is known to affect these brain regions, in IBS
patients.
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| Criteria: |
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Inclusion Criteria:
- IBS subjects with- and without comorbid somatization features will be recruited from
the sources highlighted above.
- To be eligible, subjects will have to be between 18 and 90 years of age (inclusive)
and qualify for a diagnosis of irritable bowel syndrome according to the criteria set
forth in the Rome III criteria for the Diagnosis of Functional GI Disorders.
- IBS patients will then be assessed in terms of comorbid somatization as determined
using the Patient Health Questionnaire-15 (PHQ-15).
- For this particular study, only subjects with high somatization (PHQ ≥ 10 or low
somatization (PHQ ≤5) will be considered for enrollment.
- Verification of somatization status will be performed using a formal structured
interview process (Diagnostic Interview Schedule, DIS).
- Persons are eligible to participate without regard to race or ethnicity.
- Given sex differences in cerebral responses to noxious stimuli and the greater
prevalence of IBS in women, only female participants will be sought in this study.
- Also, in view brain hemispheric differences between left- and right-hand dominant
individuals and the greater prevalence of right-handedness, all participants must be
right-handed
Exclusion Criteria:
- Persons are excluded from participation for having various psychiatric, medical, and
other characteristics.
- Psychiatric/cognitive exclusions include any of the following: active suicidal or
homicidal ideation or a history of attempted suicide, current excessive alcohol use
or other substance abuse disorders, active major depression, anxiety disorder,
bipolar depression or any psychotic disorder, unwillingness to be randomized or
provide informed consent, inability to communicate with staff or significant
cognitive impairment.
- Medical and other exclusions include any of the following: renal or hepatic disease
or impairment, diabetes, cardiovascular disease, cardiac arrythmia, cerebrovascular
disease, or breastfeeding, pregnant, or imminent intention of pregnancy, history of
seizures or primary neurological disorder, head trauma, brain damage, hyper- or
hypothyroidism, history or abdominal surgery (other than
cholecystectomy/appendectomy), or known structural GI disorder (Crohn's disease,
etc.), contraindication to MRI (metallic implant, pacemaker), or rectal balloon
distention (e.g., proctitis/colitis).
- Exclusions related to medications:
1. Analgesics (narcotics, NSAIDs; acetaminophen OK)
2. Muscle relaxants
3. Psychoactive agents (antidepressants, antipsychotics)
4. Other medications (phenytoin; amphetamines, prescription weight-loss drugs, or
benzodiazepines)
5. Thyroid medication
6. Anticholinergic medications or other IBS medications (hyoscyamine, dicyclomine)
7. Cytochrome p450 substrates
8. Participation in any clinical trial using any other drug. |