Mindfulness-based programmes reduce psychological distress (anxiety and depression) in community adults who volunteer to participate, with a small to moderate effect size. The analysis of 13 randomized controlled trials with 2,371 participants from 8 countries found a standardized mean difference of -0.32, with high confidence in the result. The effect was not clearly influenced by participants' baseline distress level, gender, age, education, or dispositional mindfulness. More research is needed to understand why outcomes vary between individuals.
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.