Table 1.

Evidence-based psychological treatments for IBS

Psychological treatment approach*	n of studies (n of participants)	Main findings	Comments
CBT248	18 RCTs (1,380)	• Symptom score: medium-to-large significant pooled effect size‡ (0.67)	• CBT was superior to waiting lists, basic support or medical treatment alone at the end of treatment but not superior to other psychological treatments
		• QOL: medium significant pooled effect size (0.48)
		• Psychological distress (depression and anxiety): small-to-medium pooled effect size (0.21)
		• NNT for CBT was 3 (95% CI: 2–6)
PIT249	2 RCTs (273)	Both studies compared PIT with `supportive listening' applied by the same therapist. Compared with controls:	• PIT is less well standardized in terms of its performance (that is, duration, setting and phases)
		• PIT significantly improved symptoms
		• PIT showed a large cost-effectiveness
		• PIT was widely acceptable
		• PIT significantly improved QOL
		• PIT significantly reduced costs
		• The calculated OR for benefit was 2.92 (95% CI: 1.76–4.83)
		• NNT for dynamic psychotherapy was 3.5 (95% CI: 2–25)
GDH247	7 RCTs (452)	• 6 of 7 RCTs reported a significant reduction (all P < 0.05) in overall gastrointestinal symptoms compared with supportive therapy only	• Very few professionals are trained for the specific implementation of GDH and therefore their services can be difficult to access
		• Response rates ranged between 24% and 73%
		• Efficacy was maintained long term in four of five studies
		• NNT was 4 (95% CI: 3–8)	• The mechanisms by which GDH exerts its effect are poorly understood
MBT215	2 RCTs (79)	• Women showed greater reductions of symptoms compared with a control group immediately after training (26.4% versus 6.2%; P = 0.006) and at 3 months follow-up (38.2% compared with 11.8%; P = 0.001)	• In another RCT, the IBS symptom severity in the mindfulness-based stress reduction group was not retained at 6 months follow-up
		• Changes in QOL, distress and anxiety were not different between groups immediately after treatment
		• Significantly greater improvement in the MBT group than in the control group evident at 3 months follow-up
		• The beneficial effects persisted for ≥3 months
Relaxation214§	6 RCTs (255)	• Overall, no benefit of relaxation training or therapy in IBS was detected in the RCTs	• The field of studies on relaxation techniques is diverse
GSHs250	10 RCTs (886)	• Compared with control conditions, a moderate effect size on symptom seventy (0.72) and a large effect size on the increase of patients' QOL (0.84) was found	• GSHs might be an easily accessible and a cost-effective treatment alternative. However, there is a wide heterogeneity and variance in its performance

The NNT data are based on Ford et al.²¹⁴. CBT, cognitive–behavioural therapy; GDH, gut-directed hypnosis; GSH, guided self-help intervention; IBS, irritable bowel syndrome; MBT, mindfulness-based therapy; NNT, number needed to treat; OR, odds ratio; PIT, psychodynamic (interpersonal) therapy; QOL, quality of life; RCT, randomized controlled trial.

^*See REF. 245.

^‡Effect size (for example, Cohen's d): effect sizes of 0.2–0.5 are regarded as small, between 0.5 and 0.8 as moderate and >0.8 as large.

^§Methods and techniques applied are progressive muscle relaxation, biofeedback and transcendental or yoga meditations.