How do mindfulness-based cognitive therapy and mindfulness-based stress reduction improve mental health and wellbeing? A systematic review and meta-analysis of mediation studies
Introduction
Although there are diverse definitions of mindfulness, it is commonly and operationally defined as the quality of consciousness or awareness that arises through intentionally attending to present moment experience in a non-judgemental and accepting way (Kabat-Zinn, 1994). Mindfulness originates from Eastern traditions and its recent popularity in Western psychology is largely due to the development and wide-spread application of standardised mindfulness-based interventions (MBIs), which integrate the essence of traditional mindfulness practice with contemporary psychological practice, in order to improve psychological functioning and wellbeing. The two most extensively employed and evaluated MBIs are mindfulness-based stress reduction (MBSR; Kabat-Zinn, 1982) and mindfulness-based cognitive therapy (MBCT; Segal et al., 2002, Segal et al., 2013), both of which are eight-week group-based therapies which teach mindfulness skills through a range of formal and informal mindfulness practices. These include mindfulness of breath, thoughts, bodily sensations, sounds, and everyday activities. A growing body of robust evidence from randomised controlled trials (RCTs) has demonstrated that MBIs are effective in improving a range of clinical and non-clinical psychological outcomes in comparison to control conditions, including anxiety (Green and Bieling, 2012, Hofmann et al., 2010), risk of relapse for depression (Kuyken et al., 2008, Teasdale et al., 2000), current depressive symptoms (Strauss, Cavanagh, Oliver, & Pettman, 2014), stress (Chiesa & Serretti, 2009), chronic pain (Grossman, Tiefenthaler-Gilmer, Raysz, & Kesper, 2007), quality of life (Godfrin and van Heeringen, 2010, Kuyken et al., 2008), psychological symptoms in patients with cancer (Ledesma & Kumano, 2009) and retrieval of specific autobiographical memories (Williams, Teasdale, Segal, & Soulsby, 2000), a reliable cognitive marker of depression (e.g. Brittlebank, Scott, Williams, & Ferrier, 1993).
Other notable interventions which involve mindfulness principles alongside other components include acceptance and commitment therapy (ACT; Hayes & Wilson, 1994) and dialectical behavioural therapy (DBT; Linehan, 1993). A consensus has not yet been reached regarding the similarity between MBSR and MBCT and these alternative interventions (Chiesa & Malinowski, 2011). However it is clear that alternative interventions differ considerably from MBSR and MBCT and each other in the duration and frequency of mindfulness practice involved, and the inclusion of mindfulness psychoeducation and non-mindfulness therapeutic ingredients. Therefore, the current review will focus solely on MBCT and MBSR to ensure consistency across studies and will use the term MBI to refer to these two interventions. These interventions have much in common in their core elements, have published therapy protocols that are adhered to in research trials and have generated the large body of evidence.
Section snippets
Hypothesised mechanisms underlying mindfulness-based interventions
Compared to the extensive evidence base for the effectiveness of MBSR and MBCT, relatively few studies have tested the mechanisms of action which causally connect changes that occur during MBIs with psychological outcomes. Kazdin (2007) emphasises several clinically relevant reasons why establishing the mechanisms of psychotherapies is crucial. These include being able to optimise therapeutic effects through enhancing active components of interventions, distinguishing between the specific and
Methods of studying the mechanisms underlying mindfulness-based interventions
To understand how change occurs during interventions, conducting mediation analyses to study the indirect influence of a treatment (X) on an outcome (Y) through a mediator (M), or intervening variable, is an essential first step (Kazdin, 2007). There are over a dozen methods of mediation analysis, most of them testing the statistical significance of a sequence of linear regression models (Baron & Kenny, 1986), or using structural equation modelling (SEM), which allows simultaneous examination
The current study
Despite systematic reviews long being advocated as a method for investigating the mediators attributed to interventions (Shadish, 1996), as interpretation of what explains a phenomenon cannot emerge from a single study (Kazdin, 2007), there are no known systematic reviews of the mechanisms of MBIs reviewing only mediation studies. Researchers have also advocated integrating meta-analytic techniques with SEM to statistically evaluate and synthesise evidence for mediation across multiple studies
Identification and selection of studies
A comprehensive search of published studies up to 10/01/2014 was conducted using the following electronic databases: PsycInfo, Scopus, Web of Knowledge, PsycArticles, ASSIA and Science Direct. The search term was: (“mindfulness based cognitive therapy” OR “mindfulness based stress reduction” OR MBSR OR MBCT) AND (mechanism* OR mediat* OR predict* OR process* OR “structural equation modelling” OR caus* OR path* OR correlat* OR relationship OR associat*).
Inclusion and exclusion criteria
Any study published in English which used
Study flow and characteristics
The search identified 1547 articles, 533 of which were duplicates. Of the remaining 1014 papers, 845 were excluded based on the title or abstract, thus the number of full-text articles assessed for eligibility was 169. The final number of studies meeting the inclusion criteria and included in the systematic review was 20. One RCT (Batink, Peeters, Geschwind, van Os, & Wichers, 2013) conducted two separate mediation analyses on subgroups in their sample and were included as two separated
Discussion
This paper's aims were threefold. First, it aimed to systematically review mediation studies in the literature on MBIs, in order to identify the mechanisms underlying MBCT and MBSR's effects on psychological functioning and wellbeing. Second, it aimed to evaluate and provide narrative summaries of the strength of evidence for each identified mechanism. Third, it aimed to conduct TSSEM analyses, to statistically synthesise evidence for mechanisms of the effects of MBIs on mental health outcomes
Conclusions
The empirical investigation of the mechanisms of change underlying the effects of MBIs on psychological functioning and wellbeing is a complex yet crucial path on which to embark in order to improve the quality, delivery and effectiveness of the interventions, develop the theoretical underpinnings of mindfulness and MBIs and inform the direction of future research. The current study is the first to systematically review mediation studies to identify and evaluate the strength and consistency of
Role of funding sources
This research was partly funded by the Economic and Social Research Council and Sussex Partnership NHS Foundation Trust in a joint Doctoral Training Scholarship provided to the first author (grant number ES/J500173/1).
Contributors
JG designed the study, developed the search strategies, conducted the literature searches and wrote the first draft of the manuscript, under the supervision of CS and KC. JG conducted the two-stage structural equation modelling analyses in collaboration with RB. All authors contributed to and have approved the final manuscript.
Conflict of interest
All authors declare that they have no conflict of interest.
Acknowledgements
This research was partly funded by the Economic and Social Research Council (grant number ES/J500173/1) and Sussex Partnership NHS Foundation Trust in a joint Doctoral Training Scholarship provided to the first author.
References (88)
- et al.
The perseverative thinking questionnaire (PTQ): Validation of a content-independent measure of repetitive negative thinking
Journal of Behavior Therapy and Experimental Psychiatry
(2011) - et al.
The effects of mindfulness-based cognitive therapy on recurrence of depressive episodes, mental health and quality of life: A randomized controlled study
Behaviour Research and Therapy
(2010) - et al.
Expanding the scope of mindfulness-based cognitive therapy: Evidence for effectiveness in a heterogeneous psychiatric sample
Cognitive and Behavioral Practice
(2012) - et al.
Acceptance and commitment therapy: Model, processes and outcomes
Behaviour Research and Therapy
(2006) - et al.
A meditation on mediation: Evidence that structural equations models perform better than regressions
Journal of Consumer Psychology
(2007) - et al.
Assessing the quality of reports of randomized clinical trials: is blinding necessary?
Controlled Clinical Trials
(1996) An outpatient program in behavioral medicine for chronic pain patients based on the practice of mindfulness meditation: Theoretical considerations and preliminary results
General Hospital Psychiatry
(1982)- et al.
How does mindfulness-based cognitive therapy work?
Behaviour Research and Therapy
(2010) - et al.
The effects of rumination and negative cognitive styles on depression: A mediation analysis
Behaviour Research and Therapy
(2008) - et al.
A review of mediators of behavior in interventions to promote physical activity among children and adolescents
Preventive Medicine
(2008)
Personality and cognitive processes: Self-criticism and different types of rumination as predictors of suicidal ideation
Behaviour Research and Therapy
Mindfulness and reduced cognitive reactivity to sad mood: Evidence from a correlational study and a non-randomized waiting list controlled study
Behaviour Research and Therapy
Cognitive reactivity and vulnerability: Empirical evaluation of construct activation and cognitive diatheses in unipolar depression
Clinical Psychology Review
Meta-analysis of the literature or of individual patient data: Is there a difference?
The Lancet
Mindfulness-based stress reduction for patients with anxiety disorders: Evaluation in a randomized controlled trial
Behaviour Research and Therapy
Comparisons between rumination and worry in a non-clinical population
Behaviour Research and Therapy
Adaptive and maladaptive self-focus in depression
Journal of Affective Disorders
Mindfulness training as a clinical intervention: A conceptual and empirical review
Clinical Psychology: Science and Practice
The moderator–mediator variable distinction in social psychological research: Conceptual, strategic, and statistical considerations
Journal of Personality and Social Psychology
How does MBCT for depression work? Studying cognitive and affective mediation pathways
PLoS ONE
The mediating effects of mindfulness and self-compassion on trait anxiety
Mindfulness
Mindfulness-based relapse prevention for addictive behaviors: A clinician's guide
Self-report mindfulness as a mediator of psychological well-being in a stress reduction intervention for cancer patients—A randomized study
Annals of Behavioral Medicine
Autobiographical memory in depression: State or trait marker
British Journal of Psychiatry
Mindfulness: Theoretical foundations and evidence for its salutary effects
Psychological Inquiry
A model for integrating fixed-, random-, and mixed-effects meta-analyses into structural equation modeling
Psychological Methods
metaSEM: Meta-analysis using structural equation modeling. R package version 0.8-4
Meta-analytic structural equation modeling: A two-stage approach
Psychological Methods
Psychological mechanisms of mindfulness-based interventions: What do we know?
Holistic Nursing Practice
Mindfulness-based approaches: Are they all the same?
Journal of Clinical Psychology
Mindfulness-based stress reduction for stress management in healthy people: A review and meta-analysis
The Journal of Alternative and Complementary Medicine
The relative benefits of meta-analysis conducted with individual participant data versus aggregated data
Psychological Methods
Effects of mindfulness-based cognitive therapy on specificity of life goals
Cognitive Therapy and Research
Repetitive negative thinking as a transdiagnostic process
International Journal of Cognitive Therapy
Distinct and overlapping features of rumination and worry: The relationship of cognitive production to negative affective states
Cognitive Therapy and Research
Mechanisms of mindfulness: A Buddhist psychological model
Mindfulness
Mindfulness training as an intervention for fibromyalgia: Evidence of postintervention and 3-year follow-up benefits in well- being
Psychotherapy and Psychosomatics
Acceptance and commitment therapy: Altering the verbal support for experiential avoidance
The Behavior Analyst
Changes in ruminative thinking mediate the clinical benefits of mindfulness: Preliminary findings
Mindfulness
The effect of mindfulness-based therapy on anxiety and depression: A meta-analytic review
Journal of Consulting and Clinical Psychology
How does mindfulness meditation work? Proposing mechanisms of action from a conceptual and neural perspective
Perspectives on Psychological Science
Systematic review of psychosocial factors at work and private life as risk factors for back pain
Spine
Is worry different from rumination? Yes, it is more predictive of psychopathology!
GMS Psycho-Social-Medicine
Wherever you go, there you are: Mindfulness meditation in everyday life
Cited by (1084)
Mindfulness-based programs sustainably increase mental health: The role of cognitive fusion and mindfulness practice
2024, Revue Europeenne de Psychologie AppliqueeBrain changes following mindfulness: Reduced caudate volume is associated with decreased positive urgency
2024, Behavioural Brain ResearchProgress in layered double hydroxides (LDHs): Synthesis and application in adsorption, catalysis and photoreduction
2024, Science of the Total EnvironmentPsychological and attentional outcomes following acute mindfulness induction among high anxiety individuals: A systematic review and meta-analysis
2024, Journal of Psychiatric Research