Efficacy of hypnosis/guided imagery in fibromyalgia syndrome - a systematic review and meta-analysis of controlled trials

BACKGROUND: Recent systematic reviews on psychological therapies of fibromyalgia syndrome (FMS) did not consider hypnosis/guided imagery (H/GI). Therefore we performed a systematic review with meta-analysis of the efficacy of H/GI in FMS. METHODS: We screened http://ClinicalTrials.gov, Cochrane Library, MEDLINE, PsycINFO and SCOPUS (through December 2010). (Quasi-) randomized controlled trials (CTs) comparing H/GI with controls were analyzed. Outcomes were pain, sleep, fatigue, depressed mood and health-related quality of life (HRQOL). Effects were summarized using standardized mean differences (SMD). RESULTS: Six CTs with 239 subjects with a median of 9 (range 7-12) H/GI-sessions were analysed. The median number of patients in the H/GI groups was 20 (range 8-26). Three studies performed follow-ups. H/GI reduced pain compared to controls at final treatment (SMD -1.17 [95% CI -2.21, -0.13]; p = 0.03). H/GI did not reduce limitations of HRQOL at final treatment (SMD -0.90 [95% CI -2.55, 0.76]; p = 0.29) compared to controls. Effect sizes on fatigue, sleep and depressed mood at final treatment and follow-up and on pain and HRQOL at follow-up were not calculated because of limited data available. The significant effect on pain at final treatment was associated with low methodological and low treatment quality. CONCLUSION: Further studies with better treatment quality and adequate methodological quality assessing all key domains of FMS are necessary to clarify the efficacy of H/GI in FMS.