Abstract
BACKGROUND: Chronic and treatment-resistant depressions pose serious problems in mental health care. Mindfulness-based cognitive therapy (MBCT) is an effective treatment for remitted and currently depressed patients. It is, however, unknown whether MBCT is effective for chronic, treatment-resistant depressed patients. METHOD: A pragmatic, multicenter, randomized-controlled trial was conducted comparing treatment-as-usual (TAU) with MBCT + TAU in 106 chronically depressed outpatients who previously received pharmacotherapy (≥4 weeks) and psychological treatment (≥10 sessions). RESULTS: Based on the intention-to-treat (ITT) analysis, participants in the MBCT + TAU condition did not have significantly fewer depressive symptoms than those in the TAU condition (-3.23 [-6.99 to 0.54], d = 0.35, P = 0.09) at posttreatment. However, compared to TAU, the MBCT + TAU group reported significantly higher remission rates (χ(2) (2) = 4.25, φ = 0.22, P = 0.04), lower levels of rumination (-3.85 [-7.55 to -0.15], d = 0.39, P = 0.04), a higher quality of life (4.42 [0.03-8.81], d = 0.42, P = 0.048), more mindfulness skills (11.25 [6.09-16.40], d = 0.73, P < 0.001), and more self-compassion (2.91 [1.17-4.65], d = 0.64, P = 0.001). The percentage of non-completers in the MBCT + TAU condition was relatively high (n = 12, 24.5%). Per-protocol analyses revealed that those who completed MBCT + TAU had significantly fewer depressive symptoms at posttreatment compared to participants receiving TAU (-4.24 [-8.38 to -0.11], d = 0.45, P = 0.04). CONCLUSION: Although the ITT analysis did not reveal a significant reduction in depressive symptoms of MBCT + TAU over TAU, MBCT + TAU seems to have beneficial effects for chronic, treatment-resistant depressed patients in terms of remission rates, rumination, quality of life, mindfulness skills, and self-compassion. Additionally, patients who completed MBCT showed significant reductions in depressive symptoms. Reasons for non-completion should be further investigated.