Mediators of a Mindfulness-Based Intervention for Younger Breast Cancer Survivors: Effects on Depressive Symptoms.

Depression is common in younger breast cancer patients and worsens outcomes. A randomized trial tested whether a mindfulness-based program (Mindful Awareness Practices, MAPs) or a psychoeducation program (Survivorship Education, SE) reduced depressive symptoms through specific psychological changes. Women under 50 with stage 0-III breast cancer were assigned to MAPs, SE, or a wait-list control. Both programs reduced depressive symptoms right after the 6-week intervention; only MAPs showed lasting reductions at 6 months. For MAPs, the effect was mediated by less rumination and fewer intrusive thoughts about cancer, plus greater self-kindness and a sense of meaning and peace. Worry mediated MAPs' effects only at postintervention. SE worked through reduced worry and intrusive thoughts at different time points. The findings clarify how mindfulness helps reduce depression in this group.

Study at a glance

Abstract

Depression is associated with poor outcomes in breast cancer patients, with higher prevalence among younger women. Although mindfulness-based interventions (MBIs) have demonstrated therapeutic effects, the mechanisms of intervention effects are poorly understood. We investigated whether rumination, self-kindness, intrusive thoughts about cancer, cancer-related worry, or a sense of meaning and peace mediated the intervention effects of an MBI, Mindful Awareness Practices (MAPs), on depressive symptoms. Additionally, we explored the same variables as mediators of a psychoeducation program, Survivorship Education (SE). Women diagnosed with stage 0-III breast cancer at age <50 years were randomized to 6 weeks of MAPs ( n = 85), SE ( n = 81), or wait-list control (WLC; n = 81). During preintervention, postintervention, and 6-month follow-up (FU), we assessed depressive symptoms, rumination, self-kindness, intrusive thoughts, worry, and meaning and peace. MAPs and SE significantly reduced depressive symptoms at postintervention, and reductions remained through 6-month FU for MAPs. Models revealed that reductions in rumination ( β = -0.68, 95% confidence interval [CI] = -1.64 to -0.07) and intrusive thoughts ( β = 1.17, 95% CI = -2.17 to -0.37) and improvements in self-kindness ( β = -1.09, 95% CI = -2.37 to -0.28) and meaning and peace ( β = -1.09, 95% CI = -3.16 to -0.56) mediated MAPs' effects at all time points. Reductions in worry ( β = -1.34, 95% CI = -2.47 to -0.45]) mediated effects at postintervention only. Worry and intrusive thoughts mediated SE effects at postintervention and 6-month FU, respectively. Findings identified depression-relevant mediators of MAPs' effects, expanding the understanding of MBI mechanisms. Results highlight pathways that could be leveraged to optimize intervention outcomes. ClinicalTrials.gov identifier: NCT03025139 .