Influence of experimentally induced anxiety on rectal sensorimotor function in healthy humans

Psychological processes, especially anxiety, may have an influence on visceral perception and gastrointestinal (GI) motor function, thereby eliciting or aggravating GI symptoms. Anxiety has been shown to affect gastric sensorimotor function but it is conceivable that anxiety affects not only the stomach but also other parts of the GI tract, such as the rectum. The aim of this study was to investigate whether experimentally induced anxiety would alter rectal sensorimotor function in health. Eighteen healthy subjects (mean age 26.97 +/- 1.75 years) underwent a rectal barostat study. To assess sensitivity to rectal distension and rectal compliance, stepwise isobaric distension was performed during anxious and neutral emotional state. Two methods of emotion induction were used simultaneously: audiotape assisted recall of a neutral or anxious autobiographical experience and viewing of a set of validated neutral or fearful facial expressions. Anxiety levels were assessed by means of the Spielberger State-Trait Anxiety Inventory (STAI) and anxiety scores on a Likert scale. Anxiety scores (AUC: 2.11 +/- 1.45 vs 42.78 +/- 6.17 mm mmHg, P < 0.0001) and STAI scores (36.06 +/- 2.09 vs 45.56 +/- 2.52, P = 0.005) confirmed the efficacy of anxiety induction. Rectal compliance was not different during anxious compared with neutral emotional state (11.62 +/- 0.93 vs 10.61 +/- 0.96 mL mmHg(-1), P = NS). Pressure and volume thresholds inducing discomfort during rectal distension were not significantly different during anxious and neutral emotional state (29.33 +/- 1.41 vs 29.78 +/- 1.49 mmHg, P = NS and 249.26 +/- 16.22 vs 231.38 +/- 21.19 mL, P = NS respectively). Contrary to its influence on gastric sensorimotor function, experimentally induced anxiety does not affect rectal sensitivity or rectal compliance in healthy subjects.