Several studies show that psychological treatments relieve symptoms for patients suffering from irritable bowel syndrome (IBS). However, there are no consistent findings that show what patient characteristics make a psychological treatment more or less likely to result in improvement. We have previously conducted a study of a newly developed internet-delivered cognitive behavioral therapy (ICBT) that emphasized exposure to IBS symptoms and IBS-related situations and reduced symptom-related avoidance. The study showed that the treatment led to improvement in IBS symptoms compared to a waiting list and that treatment gains were maintained over a 15–18 month follow-up period. The aim of the present study was to investigate several possible predictors of short- and long-term treatment outcome in terms of symptom improvement, based on data collected in the previously conducted treatment trial.

A wide range of psychological treatments have been found to reduce the symptoms of irritable bowel syndrome (IBS) but their relative effects are unclear. In this systematic review and meta-analysis, we determined the effects of psychological treatments for IBS, including subtypes of cognitive behavior therapy, versus attention controls. We searched 11 databases (March 2022) for studies of psychological treatments for IBS, reported in journal articles, books, dissertations, and conference abstracts. The resulting database comprised 9 outcome domains from 118 studies published in 1983-2022. Using data from 62 studies and 6496 participants, we estimated the effect of treatment type on improvement in composite IBS severity using random-effects meta-regression. In comparison with the attention controls, there was a significant added effect of exposure therapy (g = 0.52, 95% CI = 0.17-0.88) and hypnotherapy (g = 0.36, 95% CI = 0.06-0.67) when controlling for the pre- to post-assessment duration. When additional potential confounders were included, exposure therapy but not hypnotherapy retained a significant added effect. Effects were also larger with a longer duration, individual treatment, questionnaire (non-diary) outcomes, and recruitment outside of routine care. Heterogeneity was substantial. Tentatively, exposure therapy appears to be a particularly promising treatment for IBS. More direct comparisons in randomized controlled trials are needed. OSF.io identifier: 5yh9a.

Past research has failed to identify consistent moderators of outcomes in psychological treatments for irritable bowel syndrome (IBS). The aim of this study was to test previously identified mediators as potential moderators of the effects of exposure therapy on IBS symptoms in a previously published randomized component trial. In total, 309 participants with IBS were randomized to internet-delivered cognitive behavioral treatment that included exposure (ICBT) or to the same treatment protocol without exposure (ICBT-WE) and were asked to report on gastrointestinal symptoms at pretreatment, posttreatment and weekly during the treatment. Pretreatment scores of The Visceral Sensitivity Index (VSI) and The Irritable Bowel Syndrome Behavioral Responses Questionnaire (IBS-BRQ) (i.e., gastrointestinal anxiety and avoidance behavior) were evaluated as predictors and moderators. Piecewise latent growth curve models were employed to evaluate moderators during distinct phases of the trial, prior to and following the onset of exposure in ICBT. Results revealed that pretreatment scores on IBS-BRQ (avoidance) moderated the effect of exposure therapy during the specific phase in which exposure was implemented in ICBT, with higher avoidance scores linked to stronger positive effects of exposure. VSI did not serve as predictor nor moderator. Adding exposure to CBT seems to be especially important for persons with moderate to high levels of avoidance behaviors in order to reduce gastrointestinal symptoms.

Adequate bowel cleansing is essential for high-quality colonoscopy. Recently, a new very low-volume 1 litre (1L) polyethylene glycol (PEG) plus ascorbate solution (ASC) has been introduced. Our aims were to assess the effectiveness and tolerability of this product compared to low-volume 2L PEG-ASC and high-volume 4L PEG solutions, in a real-life setting. In six endoscopy units in Sweden, outpatients undergoing colonoscopy were either prescribed solutions according to local routines, or the very low-volume solution in split dose regimen. Bowel cleansing effectiveness and patient experience was assessed using the Boston Bowel preparation scale (BBPS) and a patient questionnaire. A total of 1098 patients (mean age 58 years, 52% women) were included. All subsegment and the total BBPS scores were significantly greater for 1L PEG-ASC in comparison to other solutions (p < 0.05 for 1L PEG-ASC and 4L PEG for transverse and left colon, otherwise p < 0.001). Nausea was more frequent with 1L PEG-ASC compared to 2L PEG-ASC (p < 0.001) and vomiting were more often reported compared to both other solutions (p < 0.01 and p < 0.05 for 2L PEG-ASC and 4L PEG, respectively). Smell, taste, and total experience was better for 1L PEG-ASC compared to 4L PEG (p < 0.001), and similar compared to the 2L PEG-ASC. In conclusion, 1L PEG-ASC leads to better bowel cleansing compared to 2L PEG-ASC or 4L PEG products, with similar or greater patient satisfaction.