Effects of laughter therapy in patients with cancer: A systematic review of randomized clinical trials

Cancer and its treatments affect patients' physical and psychological well-being. Laughter therapy is a non-pharmacological intervention with potential to relieve these effects.

To evaluate the effects of laughter therapy in patients with cancer.

A systematic review of randomized controlled trials (RCTs) was conducted to evaluate laughter therapy in cancer patients. Searches were performed in MEDLINE, EMBASE, CENTRAL, and ClinicalTrials.gov through September 1 of 2025. In pairs, the authors independently performed study selection, data extraction, and risk of bias assessment. Meta-analyses used random-effects models, and evidence certainty was assessed using the GRADE approach.

Sixteen RCTs including 1127 patients were analyzed. Laughter therapy probably results in an important reduction in anxiety (SMD: -0.54, 95% CI: -0.84 to -0.24). It probably results in little to no difference in quality of life (MD: -0.65, 95% CI: -7.15-5.86), and in nausea-vomiting severity (MD: -0.45, 95% CI: -0.80 to -0.09; moderate certainty). It may also lead to an important reduction in pain, and in stress, but may result in little to no difference in nausea frequency (low certainty). However, the evidence regarding depressive symptoms, fatigue, mood, and vomiting frequency is very uncertain (very low certainty).

Laughter therapy probably reduces anxiety and may reduce pain and stress in patients with cancer. However, these findings should be interpreted considering limitations related to risk of bias, heterogeneity among interventions, and imprecision due to small sample sizes. Further high-quality RCTs are needed to confirm these findings and compare different modalities of laughter therapy.