Mindfulness-based cognitive therapy (MBCT) added to treatment as usual reduced depressive symptoms and overall functional impairment more than treatment as usual alone in patients with persistent or recurrent major depressive disorder, with medium and small effect sizes respectively. The therapy worked better for those who started with higher levels of rumination and perseverative thinking and lower levels of self-compassion; these traits moderated the treatment's effects. No mediators of MBCT's effects were identified, as the therapy did not change the assessed potential mediators by mid-treatment. Allocating MBCT based on patients' rumination and self-compassion levels could make symptom reduction more efficient.
A 4-week therapist-assisted mindfulness-based stress reduction (MBSR) program was not superior to a minimal self-guided mindfulness-based intervention (MBI) for improving mental health among frontline healthcare workers during the COVID-19 pandemic. In a randomized trial with 201 participants, both interventions led to similar, significant reductions in depressive, anxiety, and somatic symptoms from baseline to 6-month follow-up (Cohen's d -0.78 for MBSR, -0.72 for self-guided MBI). The therapist-assisted MBSR showed a greater reduction in symptoms immediately after the intervention and exclusively increased posttraumatic growth at that point. Both approaches improved posttraumatic symptoms, insomnia, repetitive negative thinking, mental well-being, mindfulness, and self-compassion.