Table 4 Characteristics of randomised controlled trials of psychological therapies versus control therapy or a physician’s “usual management” in irritable bowel syndrome (IBS)

Study (first author, year and reference no.)	Country	Setting	Diagnostic criteria used for IBS	Criteria used to define symptom improvement following therapy	Sample size	Psychological therapy used	Duration of therapy (no. of sessions)	Jadad score
Neff 198742	USA	Tertiary care	Clinical diagnosis	⩾50% reduction in baseline symptom score	19	Multi-component psychological therapy	8 weeks (12)	2
Lynch 198941	Canada	Tertiary care	Clinical diagnosis	⩾50% reduction in diary rating of symptoms	21	Relaxation therapy	2 months (8)	2
Guthrie 199150	England	Tertiary care	Clinical diagnosis and investigations	Patient-reported improvement in global symptoms	102	Dynamic psychotherapy	3 months (7)	2
Shaw 199144	Wales	Tertiary care	Clinical diagnosis and investigations	Patient-reported overall benefit from treatment	35	Stress management programme	6 months (6)	1
Blanchard 199239	USA	Tertiary care	Clinical diagnosis and investigations	⩾50% reduction in baseline symptom score	20 and77*	Multi-component psychological therapy	8 weeks (12)	2
Blanchard 199338	USA	Tertiary care	Clinical diagnosis and investigations	⩾50% reduction in baseline symptom score	23	Progressive muscle relaxation	8 weeks (10)	2
Greene 199440	USA	Tertiary care	Clinical diagnosis and investigations	⩾50% reduction in baseline symptom score	20	Cognitive behavioural therapy	8 weeks (10)	1
Payne 199543	USA	Tertiary care	Rome I and investigations	⩾50% reduction in baseline symptom score	22	Cognitive behavioural therapy	8 weeks (10)	2
Galovski 199862	USA	Tertiary care	Clinical diagnosis	⩾50% reduction in baseline symptom score	12	Hypnotherapy	6 weeks (12)	2
Vollmer 199847	USA	Tertiary care	Rome I and investigations	⩾50% reduction in baseline symptom score	34	Cognitive behavioural therapy	10 weeks (10)	2
Keefer 200148	USA	Tertiary care	Clinical diagnosis	⩾50% reduction in baseline symptom score	15	Relaxation response meditation	6 weeks (6)	2
Boyce 2003‡63	Australia	Tertiary care	Rome I and investigations	⩾1 standard deviation decrease in baseline symptom score†	105	Cognitive behavioural therapy and relaxation therapy	8 weeks (8)	3
Creed 2003‡64	England	Tertiary care	Rome I	Patient-reported improvement in global symptoms	171	Dynamic psychotherapy	3 months (8)	3
Drossman 2003‡37	USA	Tertiary care	Rome I	⩾Score of 28 on treatment satisfaction questionnaire	169	Cognitive behavioural therapy	12 weeks (12)	3
Tkachuk 200345	Canada	Tertiary care	Rome I and investigations	Patient-reported improvement in global symptoms	28	Cognitive behavioural therapy	9 weeks (10)	2
Heitkemper 2004‡65	USA	Tertiary care	Rome I	⩾50% reduction in symptom score	95	Multi-component psychological therapy	8 weeks (8)	2
Simren 200466	Sweden	Tertiary care	Rome II and investigations	Patient-reported improvement in global symptoms	28	Hypnotherapy	12 weeks (12)	3
Kennedy 2005‡49	England	Primary care	Clinical diagnosis	Improvement in symptom severity banding by one band (graded severe to none on a four-point Likert-scale)	149	Cognitive behavioural therapy	6 weeks (6)	3
Sanders 2007‡67	USA	Tertiary care	Rome II and investigations	⩾50% reduction in baseline symptom score	28	Self-administered cognitive behavioural therapy	10 weeks (5)	3
van der Veek 200746	Holland	Tertiary care	Rome II	Reliable change index ⩾1.96 (pre-therapy score minus post-therapy score divided by standard error of the difference)	105	Relaxation training	3 months (4)	3

*Two separate studies reported in one paper.
†Criteria defined as part of the current systematic review in the absence of an author-specified definition.
‡Further information obtained from original investigators.