Symptom worsening in mindfulness-based cognitive therapy

The individual participant data (IPD) meta-analysis of mindfulness-based cognitive therapy (MBCT) for the prevention of depressive relapse or recurrence described by Kuyken et al. has supported the dissemination of MBCT as a frontline treatment for depression. MBCT is now recommended in multiple clinical guidelines including the National Institute for Health and Care Excellence in the UK and is widely implemented across health care systems. Since this meta-analysis was published, questions have been raised regarding the safety of mindfulness-based interventions. Two recent studies examined the occurrence of meditation-related harm in the context of MBCT. Although definitions and rates of harm differed across these studies, both documented cases defined as reflecting patient-reported harm. Importantly, neither study included a control condition, making it impossible to evaluate the degree to which MBCT increased the likelihood of these experiences occurring. Establishing whether MBCT increases the likelihood of poor outcomes relative to a control condition is crucial for weighing the costs relative to benefits of this treatment. IPD allows evaluation of symptom worsening following treatment relative to controls, which is one indicator of treatment-related harm when examined within a randomized trial context in which causality can be inferred. The present study is a preregistered secondary analysis of the Kuyken et al. IPD evaluating odds of symptom worsening for MBCT vs controls.