What this Trial Is About

The overall aim of this observational study is to investigate how individual differences influence the effects of mindfulness meditation to uncover for whom mindfulness is beneficial and for whom it may be harmful. The first objective is to identify the mechanisms underlying the effects of mindfulness meditation on mental health. The second objective is to examine how three candidate factors, namely trauma symptoms, tendency to dissociate, and repetitive negative thinking, influence the effect of mindfulness meditation on mental health. Adults who enrolled for a Mindfulness-Based Intervention (MBI) at the participating sites (n=120 in total) will be invited to participate. Before the start of the MBI, after half of the sessions, at the end of the MBI and at 3-months follow-up, participants will complete self-report questionnaires. The main outcomes are symptoms of anxiety and depression, quality of life, wellbeing, and adverse effects resulting from the MBI. A subset of participants will be invited for a semi-structured interview after the end of the intervention. Update December 2024: Instead of analysing all subsamples recruited from the different sites separately, the investigators will now analyse all participants from all sites jointly. This amendment has two reasons. First, analysing all participants jointly allows to statistically compare the differences in effects across sites by including a variable that indicates from which site a participant was recruited. If the subsamples are analysed separately, the investigators can only compare the results at face-value but cannot determine whether the effects are statistically different across sites. Second, recruitment could not start at one site because of a restructuring of the mindfulness interventions there and the investigators are experiencing recruitment difficulties in a second site (recruited 5 participants within 1.5 years). Thus, it will not be feasible to recruit 120 participants per site. For those two reasons, the investigators decided to analyse all participants jointly and only recruit 120 participants in total for the quantitative part of this study (see updated study protocol).

Who Fares Best With Mindfulness Meditation