Irritable Bowel Syndrome (IBS) Functional Magnetic Resonance Imaging (fMRI) With Desipramine

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.


Eligibility Criteria:
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.