The effect of psychological stress on symptom severity and perception in patients with gastro-oesophageal reflux

Abstract

Objective

Using an experimental paradigm this investigation explored whether exposure to psychological stress would produce a significant increase in acid-reflux episodes or modify subjective perceptions of gastro-oesophageal reflux (GOR) symptoms.

Methods

Forty-two patients presenting with heartburn and acid regurgitation underwent 24-h oesophageal pH monitoring. During the last 90 min of this monitoring period, 21 patients received a psychological stressor, while the remaining participants were randomly assigned to a no-stress control condition. State anxiety and subjective GOR symptom ratings were obtained 1 min pretest, 1 min posttest, and 40 min posttest. Cortisol samples were collected at 10-min intervals.

Results

The stressor induced a significant increase in cortisol and state anxiety; however, this was not associated with any increase in reflux. Instead, the experimental group reported a dissociation between objectively measured reflux episodes and subjective symptom ratings. A similar pattern was established for participants who reported greater state anxiety, produced larger cortisol responses, or exhibited certain stress-related personality characteristics.

Conclusion

The perception of symptoms in the absence of increased reflux when one is stressed may account for low response rates to traditional treatments. This highlights a need to bridge the gap between psychosomatic research and clinical practice to develop more successful GOR therapies.

Introduction

Heartburn and acid regurgitation, caused by the reflux of gastric acid into the oesophagus, are the main symptoms of gastro-oesophageal reflux disease (GORD). It can also present with chest pain, belching, nausea, or nonobstructive dysphagia secondary to GORD [1]. Preclinical levels of gastro-oesophageal reflux (GOR) are increasingly common in Western societies and currently affect up to 40% of the U.S. population [2]. Despite a wealth of recent research, a number of uncertainties surround its aetiology, particularly with symptom perception. Evidence now suggests that psychosocial influences, such as stress or stress-related personality characteristics, may play an important role in the presentation, diagnosis, and treatment of this disease [3], [4], [5].

Stress is believed to exacerbate GOR symptomatology by increasing resting lower oesophageal sphincter (LOS) pressure, impairing sphincter relaxation and thus delaying acid clearance from the oesophagus [6]. However, while the application of psychological relaxation techniques has led to significant reductions in reported heartburn and duration of oesophageal acid exposure [7], clinical evidence for a decisive direct relationship between stress and GOR is still rather uncertain, with results reporting both an increase and decrease in GOR symptomatology during periods of stress [3], [8], [9], [10], [11], [12]. An indirect relationship between stress and GOR is also suggested. For example, using an acid-perfusion test to reproduce reflux symptoms, it has been discovered that some reflux-negative heartburn patients report reflux-related pain [13]. Moreover, the alteration of symptom perception is believed to occur during periods of heightened arousal [14]. This may account for the proportion of patients with normal endoscopy who report the presence of typical reflux symptoms [13], [15]. Further exploration of both these relationships is therefore necessary.

Empirical evidence for the influence of individual differences in stress responses in GOR patients is fairly limited [16]. Johnston et al. [17] report that although a stress task did not produce an increase in reflux, symptom ratings of subjects with low trait anxiety were similar for both stress and neutral tasks, and their ratings were generally consistent with oesophageal pH data. However, a dissociation between symptom self-rating and oesophageal pH data was present for highly anxious subjects. The perceived increase of reflux symptoms, in the absence of actual increased acid reflux, has also been reported in a subset of highly anxious GOR patients exposed to a stressor [18]. Similarly, patients with dyspepsia of unknown origin had significantly higher anxiety and tension scores than symptom-positive dyspepsia subjects [19]. Current literature seems to suggest a pivotal role of anxiety in altered symptom perception, but a wider range of stress-related characteristics needs investigation.

Limitations of previous methods employed may also explain the uncertainties surrounding the relationship between stress and GOR. For example, previous research has often involved very small sample sizes [11], [12]. Investigators frequently used physical or purely cognitive stressors [3], [8], [11], [12], even though more valid ones such as interview scenarios have been shown to increase oesophageal contractions [20]. The measurement of stress is also inconsistent between studies comparing the effect of actual stress (measurement of physiological processes) with that of perceived stress (participant's subjective rating). Control groups are often not employed, and psychological stress resulting from very recent insertion of the pH probe is seldom taken into account.

One major difficulty of work in this area is that, although relationships between psychological stress and gastro-oesophageal function are easily established, the direction of causality is far more difficult to ascertain. The current investigation therefore adopted an experimental design to assess oesophageal acid level at the exact point that a psychological stressor was administered (additionally using cortisol as a biological marker of the stress response). Post hoc, the sample was also divided into high and low state anxiety ratings and high and low biological markers (cortisol) of stress for additional analysis.

In summary, the current literature suggests a correlation between stress and GOR. However, the present evidence surrounding the exact nature of this relationship is contradictory. The investigation reported here had three main aims. First, to determine whether exposure to a psychological stressor is causally related to a change in acid reflux, or whether stress merely acts to alter perception of GOR symptoms; second, to assess whether state anxiety influences the relationship between stress and GOR; and third, to establish whether stress-related personality characteristics could affect the relationship between stress and acid secretion.