What Works in Mindfulness Interventions for Medically Unexplained Symptoms? A Systematic Review

Background/Purpose: Mindfulness-based interventions (MBIs) have been used in medically unexplained symptoms (MUS). This systematic review describes the literature investigating the general effect of MBIs on MUS and identifies the effects of specific MBIs on specific MUS conditions. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis Guidelines (PRISMA) and the modified Oxford Quality Scoring System (Jadad score) were applied to the review, yielding an initial 1,556 articles. The search engines included PubMed, ScienceDirect, Web of Science, Scopus, EMBASE, and PsychINFO using the search terms: mindfulness, or mediations, or mindful or MBCT or MBSR and medically unexplained symptoms or MUS or Fibromyalgia or FMS. A total of 24 articles were included in the final systematic review. Results/Conclusions: MBIs showed large effects on: symptom severity (d  = 0.82), pain intensity (d  = 0.79), depression (d  = 0.62), and anxiety (d  = 0.67). A manualized MBI that applies the four fundamental elements present in all types of interventions were critical to efficacy. These elements were psycho-education sessions specific to better understand the medical symptoms, the practice of awareness, the nonjudgmental observance of the experience in the moment, and the compassion to ones' self. The effectiveness of different mindfulness interventions necessitates giving attention to improve the gaps that were identified related to home-based practice monitoring, competency training of mindfulness teachers, and sound psychometric properties to measure the mindfulness practice.