Abstract
OBJECTIVE: We examined the effects of Mindfulness-based interventions (MBIs) on depressive symptoms in women with breast cancer and examined the moderating effects of participant characteristics, research methodologies, and features of interventions. METHODS: We systematically searched 12 databases through November 2022 without date restrictions using the following search terms: (mindful* or meditation) AND (cancer OR neoplasm) AND (depress*). Studies included were primary studies evaluating MBIs in women with breast cancer who also had depression. Studies were included if they used a control group and were written in English. We used a random-effects model to compute effect sizes (ESs) using Hedges' g, forest plot, and Q and I(2) statistics as measure of heterogeneity. We also requested moderator analyses. RESULTS: We found 19 studies with 2139 participants (49.4 ± 8.3 years old) that met inclusion criteria for this meta-analysis and systematic review. Overall, women in MBI groups demonstrated significantly lower levels of depression (g = 0.48, 95% CI:0.159, 0.792, P < .001) compared to women in control groups. Regarding moderators, providing MBIs with a home assignment component showed a significantly greater effect on decreasing depressive symptoms (g = 1.75) compared to MBIs without a home assignment component (g = 0.20). When researchers used concealed allocation technique, the interventions demonstrated lower effects on depression than when concealed allocation (g = 0.11vs g = 1.33, P ≤ .001) was not reported. Additionally, when researchers reported high rates of sample attrition, they found a lower effect size on depression (β = -.019, Q = 3.97, P = .046) indicating that attrition moderates the effect. CONCLUSION: MBIs are moderately effective interventions to reduce depressive symptoms among women with breast cancer. Clinicians might consider encouraging MBIs as adjunct/alternative treatments for women with breast cancer to manage symptoms of depression. Interventions that incorporat home assignments for practicing mindfulness are likely to have a greater effect on reducing depressive symptoms. Additionally, methods including concealed allocation and attrition rate were moderators of the effects of MBIs on depression in women with breast cancer.