Effects of laughter therapy on depression and anxiety: A dose-response meta-analysis with trial sequential analysis

Laughter therapy serves as a practical and efficient complementary alternative therapy for psychological distress. This meta-analysis aimed to further investigate the efficacy of laughter therapy by integrating trial sequential analysis (TSA) and exploring the optimal treatment duration using a dose-response meta-analysis.

This systematic review conducted randomized controlled trials across major databases (PubMed, EMBASE, PsycINFO, and the Cochrane Library), from their inception to November 12, 2023. Included articles using laughter therapy for depression, anxiety, stress, pain, or quality of life. We employed TSA to assess evidence conclusiveness and the dose-response meta-analysis to explore optimal treatment length.

Thirty-three studies were included in the analysis. The following information was extracted: information on publication, patients' characteristics, intervention type, intervention duration. Information on outcomes (e.g., type of outcome, measurement tool) and statistical data needed for effect size estimation were extracted independently by two authors (THL & CYL).

Laughter therapy significantly reduced depression (standardized mean differences [SMD] = -0.9; 95% CI: -1.29 to -0.52), anxiety (SMD = -0.83; 95% CI: -1.16 to -0.50), and stress (SMD = -0.68; 95% CI: -1.02 to -0.33) (all p < .001). The dose-response meta-analysis revealed that longer cumulative treatment durations up to 400 min for depression and 600 min for anxiety yielded greater improvements, with benefits plateauing thereafter. Our subgroup analyses showed that laughter-inducing therapies significantly alleviate depression, anxiety and stress across various ages, patient conditions, and care settings.

Laughter therapy effectively alleviates depression, anxiety, and stress, with optimal durations identified for these benefits. The study strengthens the evidence base for laughter therapy and provide supportive evidence for conducting more future RCTs to clinical implication.