Irritable bowel syndrome (IBS) is a chronic functional bowel disorder that is thought to be due to a disorder of brain-gut function. Drugs acting centrally, such as antidepressants, and psychological therapies may, therefore, be effective.
We updated a previous systematic review and meta-analysis of randomized controlled trials (RCTs). MEDLINE, EMBASE, PsychINFO, and the Cochrane Controlled Trials Register were searched (up to July 2017). Trials recruiting adults with IBS, which compared antidepressants versus placebo, or psychological therapies versus control therapy or "usual management" were eligible. Dichotomous symptom data were pooled to obtain a relative risk (RR) of remaining symptomatic after therapy, with a 95% confidence interval (CI).
The search strategy identified 5316 citations. Fifty-three RCTs, reported in 51 separate articles, were eligible for inclusion: 17 compared antidepressants with placebo, 35 compared psychological therapies with control therapy or "usual management", and one compared both psychological therapy and antidepressants with placebo. Four of the trials of psychological therapies, and one of the RCTs of antidepressants, were identified since our previous meta-analysis. The RR of IBS symptoms not improving with antidepressants versus placebo was 0.66 (95% CI 0.57-0.76), with similar treatment effects for both tricyclic antidepressants and SSRIs, although with heterogeneity between RCTs of the latter (I2 = 49%, P = 0.07). The RR of symptoms not improving with psychological therapies was 0.69 (95% CI 0.62-0.76). Cognitive behavioral therapy, relaxation therapy, multi-component psychological therapy, hypnotherapy, and dynamic psychotherapy were all beneficial when data from two or more RCTs were pooled. There was significant heterogeneity between studies (I2 = 69%, P < 0.001) and significant funnel plot asymmetry. There were also issues regarding trial design, including lack of blinding.
Antidepressants are efficacious in reducing symptoms in IBS patients. Psychological therapies also appear to be effective treatments for IBS, although there are limitations in the quality of the evidence, and treatment effects may be overestimated as a result.