Psychophysiological response to a laboratory challenge in women with and without diagnosed irritable bowel syndrome.

The purpose of this study was to describe and compare physiological variables at baseline and in response to laboratory stress among women diagnosed with irritable bowel syndrome (IBS, n = 26), women with undiagnosed chronic gastrointestinal symptoms consistent with IBS (IBS-NP, n = 24), and asymptomatic women (n = 22). Urine catecholamine levels were measured in the first voided specimen on the morning of testing. Cardiovascular variables were measured at baseline and repeatedly during the Stroop Color-Word Conflict Test (Stroop). Women in the IBS group had higher baseline systolic blood pressure (SBP) than the control group and higher basal urine norepinephrine (NE) levels than the IBS-NP group. Control for activity or body mass reduced the group difference in SBP to nonsignificance but did not affect the observed difference in urine NE. There were no significant differences among the groups in other baseline values or in response to the Stroop. These results suggest that, despite higher basal urine catecholamine levels, cardiovascular reactivity to a cognitive challenge in a laboratory setting is not elevated in women with diagnosed IBS.