Temporal Changes in Mindfulness Skills and Positive and Negative Affect and Their Interrelationships During Mindfulness-Based Cognitive Therapy for Cancer Patients

Objectives While efficacy research on mindfulness-based interventions in cancer patients is available, research on possible mechanisms of change is lacking. The current study investigated general and week-to-week changes and interrelations in mindfulness and positive and negative affect in Mindfulness-Based Cognitive Therapy (MBCT) for cancer patients. Methods In total, 163 cancer patients completed face-to-face or online MBCT. Mindfulness and positive and negative affect were measured weekly during the intervention. Autoregressive latent trajectory models were used to evaluate general and week-to-week effects. Results Overall, mindfulness and positive affect increased, and negative affect decreased during MBCT. Higher general levels of mindfulness were associated with higher general levels of positive affect. Regarding week-to-week effects, positive affect in weeks 3, 7, and 8 predicted an increase in mindfulness in the following week. Various general relations were observed between mindfulness and negative affect, showing that higher mindfulness was related to less negative affect. To the contrary, week-to-week effects showed higher mindfulness consistently predicted increased negative affect in the subsequent week. Conclusions In cancer patients, mindfulness appeared to be more robustly related to negative than to positive affect. Furthermore, mindfulness in one week was related to an increase of negative affect in the following week, possibly due to turning towards previously suppressed negative emotions. However, when focusing on the whole course from start to end, the increase of mindfulness was related to a decrease of negative affect, possibly due to acceptance of and exposure to negative emotions. Our findings reveal the complexity of mechanisms of MBCT and illustrate the necessity of sophisticated models with longitudinal measurements to truly elucidate these mechanisms. Trial Registration Clinical Trials.gov: NCT02138513.