Mindfulness interventions for psychosis: a meta-analysis.

Background: An increasing number of mindfulness interventions are being used with individuals with psychosis or schizophrenia, but no known meta-analysis has investigated their effectiveness.

Objective: To evaluate the efficacy of mindfulness interventions for psychosis or schizophrenia, we conducted an effect-size analysis of initial studies.

Data Sources: A systematic review of studies published in journals or in dissertations in PubMED, PsycINFO or MedLine from the first available date until July 25, 2013.

Review Methods: A total of 13 studies (n=468) were included.

Results: Effect-size estimates suggested that mindfulness interventions are moderately effective in pre-post analyses (n=12; Hedge's g=.52). When compared with a control group, we found a smaller effect size (n=7; Hedge's g=.41). The obtained results were maintained at follow-up when data were available (n=6; Hedge's g=.62 for pre-post analyses; results only approached significance for controlled analyses, n=3; Hedge's g=.55, p=.08). Results suggested higher effects on negative symptoms compared with positive ones. When combined together, mindfulness, acceptance, and compassion strongly moderated the clinical effect size. However, heterogeneity was significant among the trials, probably due to the diversity of interventions included and outcomes assessed.

Conclusion: Mindfulness interventions are moderately effective in treating negative symptoms and can be useful adjunct to pharmacotherapy; however, more research is warranted to identify the most effective elements of mindfulness interventions.