Effects of Loving-Kindness and Compassion Meditation on Anxiety: A Systematic Review and Meta-Analysis

It is debatable whether loving-kindness and compassion meditation (LKCM) effectively reduces anxiety, and previous studies have reported inconsistent findings. This study provides a systematic review and meta-analysis of the effects of LKCM on anxiety. Studies that took LKCM as the main body and measured anxiety as an outcome were included. There were no exclusion criteria for sample characteristics or control groups. Among 327 empirical studies published up to March 2022 on LKCM, 59 measured anxiety as an outcome. Meta-analyses showed that LKCM interventions are effective in reducing anxiety (d = -0.28, k = 19, n = 1284 for randomized controlled trials; d = -0.48, k = 26, n = 1177 for nonrandomized trials; d = -0.58, k = 6, n = 503 for laboratory experiments). The heterogeneity was high between studies. Subgroup analyses for randomized controlled trials found that studies combining loving-kindness meditation and mindfulness meditation outperformed studies adopting loving-kindness meditation alone. Moreover, studies with waitlist controls had greater effect sizes than studies with active controls. The type of anxiety, participant characteristics, protocol, or length of intervention had no statistically significant moderating effects. Individual studies supported mindfulness and self-compassion as important mechanisms, but the amount of meditation practice made a limited contribution. LKCM interventions can be effective in reducing anxiety. The incremental value of combining mindfulness meditation with loving-kindness meditation is encouraging. More research is needed, especially on specific populations suffering from anxiety disorders. PROSPERO CRD42021245515