Title: Mindfulness-based interventions for mental health promotion: an individual participant data meta-analysis to assess comparative effects and predictors of differential response
Funder: Department of Health and Social Care

Abstract: BackgroundMental wellbeing predicts mental and physical health outcomes, and has been hailed as one of the ultimate aims in public health in recent years10. Universal interventions to promote mental wellbeing and prevent mental health problems are thought to be effective because more people from low risk groups will ultimately develop a problem than those at risk. Combining preventative mental health interventions with stratified medicine approaches could lead to advantages in effectiveness, cost-effectiveness, and intervention harm minimisation11.Mindfulness-based interventions (MBIs) to promote mental health have become extremely popular. Major UK organisations have introduced them, including 30 universities and several NHS trusts, civil service departments and private employers12 13. However, an overview of systematic reviews conducted for this application revealed that the evidence for preventative MBIs is weak, consisting of scattered small randomised controlled trials (RCTs) suggesting positive effects but high inter-individual variability. Many uncertainties remain: most RCTs have high risk of type I and II errors; there are publication bias concerns; effects of different types of MBIs are obscure; results against active controls are mixed; and there is evidence that not everyone benefits from mindfulness training. High-quality systematic reviews and meta-analyses on the topic are lacking. In 2015 an All-Party Parliamentary Group recommended that the NIHR funds research on mindfulness as a public health preventative intervention13.An individual participant data (IPD) meta-analysis of preventative MBIs would cost-effectively improve the quality of inferred results based on existing data overcoming some of the existing biases, and would provide the largest possible sample size to explore how MBI effectiveness varies as function of individual and study differences14.Research aimsThe primary aims of this study are to: (a) evaluate the effectiveness of MBIs for reducing distress, anxiety and depression, and improving mental wellbeing, self-care and performance among community adults, compared with no intervention or a comparator intervention; and (b) assess predictors of differential intervention response at individual (e.g. baseline mental distress) and study (e.g. length of intervention) levels.Plan of investigationTo address the research aims, an IPD meta-analysis will be conducted. Published and unpublished RCTs, assessing MBIs of at least four sessions, among adult participants living in the community not selected for having any particular illness or disability will be systematically reviewed following a prospectively registered protocol with pre-defined outcomes. RCTs' risk of bias will be assessed, and aggregate data meta-analyses will be conducted.Authors of trials with 90 or more participants will be invited to contribute IPD15. Sixteen studies from the overview (N=2,886) are eligible. Thanks to preliminary agreements with nine of them, 61% of the eligible trials' participants (N=1,765) are readily available. Data will be checked, queried, standardised, and re-analysed for each RCT following the intention-to-treat principle. IPD random-effects meta-analyses will be performed comparing MBIs against active (non-specific and other interventions) and passive control groups. Heterogeneity, publication bias and sensitivity analyses will be carried out. Predetermined predictors differential response to the intervention will be assessed and prognostic modelling will be attempted16.Steering and Stakeholder groups including members of the public will provide input throughout the life of the project, from protocol decisions to interpretation and dissemination of results, following a co-production model5.Benefit for the publicOutputs will significantly benefit the public within five years of project completion by determining the effectiveness of preventative MBIs and improving their targeting in a variety of settings, consequently improving communities' mental health and wellbeing, and generating a more efficient use of public resources.Impact will also be achieved by increasing public awareness and understanding of preventative research and by promoting the adoption of evidence-based stress management techniques.

Lay abstract: Mindfulness: Helping people to feel goodPublic health organisations in the UK are interested in finding ways to improve the mental wellbeing of the general public, as mental wellbeing is linked to better health. One way of doing this is to offer techniques to the public that are effective in promoting mental health and preventing mental problems.One set of techniques that many people find helpful is mindfulness training. Mindfulness training is about learning to pay attention to what is happening at the present moment with an attitude of curiosity and kindness. Some mindfulness courses are specifically designed for people who are clinically unwell, but mindfulness practices were traditionally intended for anyone to improve their mental wellbeing.Mindfulness courses to increase wellbeing and reduce stress have become very popular. Many organisations in the UK now offer mindfulness training, including universities and civil service departments.If preventative mindfulness courses are found to be effective for most people, and people are interested in learning mindfulness, then there are good grounds for offering these courses as part of public health programmes. However, the research evidence for offering mindfulness courses in this way is weak: While many studies show that preventative mindfulness training is beneficial, most are poorly designed so that you cannot be sure of the results. There are concerns that studies showing no benefit have not been published in prominent scientific journals and so few people know about them. This could give an overly optimistic picture of how helpful mindfulness is. Mindfulness courses come in different shapes and sizes', and we don't know which ones work best, for whom and in which circumstances. When mindfulness training is compared with other feel-good practices such as physical exercise, it is not clear which one is best. Even less clear is who benefits most from each. There is evidence that not everyone benefits from mindfulness training. It may even be harmful for some people, but at present this is poorly understood. Policy makers need high quality reviews and analyses that systematically take all of these factors into account before deciding whether or not to offer preventative mindfulness training to the public at large. In 2015 an All-Party Parliamentary Group recommended that the National Institute of Health Research invite bids for research to explore the potential of mindfulness as a public health preventative intervention.Finding out what works for whomI propose to conduct a systematic review and meta-analysis of all the studies that I can find on mindfulness training for mental health promotion. Systematic review is a research technique that uses clear methods to identify and critique studies. Meta-analysis is a statistical method of combining the data from these studies to show an overall effect; a kind of average result. I plan to do the most refined and reliable type of meta-analysis, one where all the data from each individual in each study is combined. This approach enables researchers to ask questions that cannot be answered by a single study, such as which groups of individuals are more likely to be helped by mindfulness training. This complex type of meta-analysis is called an individual participant data (IPD) meta-analysis. I propose to train in IPD meta-analysis statistical methods, and to conduct an IPD meta-analysis to study the following: Comparative effects: To determine whether mindfulness training reduces distress, anxiety and depression, and improves mental wellbeing, self-care and performance among adults living in the community, compared with no training at all or with other feel-good practices. Predictors of differential response: To find out which types of people benefit from the different types of mindfulness courses available. I will invite members of the public interested in mental health promotion or mindfulness, health service managers, and mindfulness teachers to get involved early on in the research. Their experience will help to understand aspects of mental health promotion in daily life and society, how different mindfulness courses work for different types of people, and what effects to look out for in this research. Together we will work on all aspects of the project. For example, we will train together in effective communication, and then make a plan to share information about the research and findings with various audiences using academic, stakeholder and public networks.This study will determine whether preventative mindfulness courses really help people to feel better and avoid mental health problems, or whether they are just a fad'. It will also help to understand who to offer mindfulness to, and in what ways.

Research activity codes: 6.6 PSYCHOLOGICAL AND BEHAVIOURAL;6.7 PHYSICAL
Health categories: MENTAL HEALTH