Abstract: Psychological interventions as a group  The SMD for symptom score improvement at 2 and 3 months was 0.97 (95% CI 0.29 to 1.65) and 0.62 (95% CI 0.45 to 0.79) respectively compared to usual care. Against placebo, the SMDs were 0.71 (95% CI 0.08 to 1.33) and -0.17 (95% CI -0.45 to 0.11) respectively. For improvement of abdominal pain, the SMDs at 2 and 3 months were 0.54 (95%CI 0.10 to 0.98) and 0.26 (95% CI 0.07 to 0.45) compared to usual care. The SMD from placebo at 3 months was 0.31 (95% CI -0.16 to 0.79). For improvement in quality of life, the SMD from usual care at 2 and 3 months was 0.47 (95%CI 0.11 to 0.84) and 0.31 (95%CI -0.16 to 0.77) respectively.   Cognitive behavioural therapy  The SMD for symptom score improvement at 2 and 3 months was 0.75 (95% CI -0.20 to 1.70) and 0.58 (95% CI 0.36 to 0.79) respectively compared to usual care. Against placebo, the SMDs were 0.68 (95% CI -0.01 to 1.36) and -0.17 (95% CI -0.45 to 0.11) respectively. For improvement of abdominal pain, the SMDs at 2 and 3 months were 0.45 (95% CI 0.00 to 0.91) and 0.22 (95% CI -0.04 to -0.49) compared to usual care. Against placebo the SMD at 3 months was 0.33 (95% CI -0.16 to 0.82). For improvement in quality of life, the SMDs at 2 and 3 months compared to usual care were 0.44 (95% CI 0.04 to 0.85) and 0.92 (95% CI 0.07 to 1.77) respectively. Interpersonal psychotherapy  The RR for adequate relief of symptoms was 2.02 (95% CI 1.13 to 3.62), RD 0.30 (95% CI 0.13 to 0.46), NNT 4 for comparison with care as usual. The SMD for improvement of symptom score was 0.35 (95% CI -0.75 to 0.05) compared with usual care.   Relaxation/Stress management  The SMD in symptom score improvement at 2 months was 0.50 (95%CI 0.02 to 0.98) compared with usual care. The SMD in improvement of abdominal pain at 3 months was 0.02 (95%CI -0.56 to 0.61) compared with usual care.   Long term results  Very few long term follow-up results were available. There was no convincing evidence that treatment effects were sustained following completion of treatment for any treatment modality. Psychological interventions may be slightly superior to usual care or waiting list control conditions at the end of treatment although the clinical significance of this is debatable. Except for a single study, these therapies are not superior to placebo and the sustainability of their effect is questionable. The meta-analysis was significantly limited by issues of validity, heterogeneity, small sample size and outcome definition. Future research should adhere to current recommendations for IBS treatment trials and should focus on the long-term effects of treatment.

Plain-language summary: In this review, the effectiveness of psychological therapies for adult patients with irritable bowel syndrome was evaluated. Studies involving cognitive behavioural therapy, interpersonal psychotherapy and relaxation therapy or stress management were reviewed. Although it is difficult to draw conclusions because of differences between studies and quality issues, the results suggest that cognitive behavioural therapy and interpersonal psychotherapy may be effective immediately after finishing treatment. It is unclear whether the effects of these therapies are sustained thereafter. These results have to be interpreted with caution as the quality of the studies was sub-optimal. Physicians should be aware of the limitations of these therapies and should choose an appropriate therapy based on the individual patient's characteristics.