Title: The Effects of Melatonin in Parkinson’s Disease: A Systematic Review and Meta-Analysis of Double-Blind, Placebo-Controlled RCTs
Authors: Vishnu Vardhan Byroju, Jamir Pitton Rissardo, and Ana Leticia Fornari Caprara
Conference: 2025 International Congress of Parkinson's Disease, Honolulu, HI
Objective
To assess the efficacy of melatonin on motor symptoms, sleep quality, and quality of life in patients with Parkinson's disease (PD) by performing a meta-analysis of available double-blind, placebo-controlled randomized controlled trials (RCTs) retrieved from PubMed.
Background
Melatonin is commonly used for sleep disturbances in PD, but its broader impact on motor function and quality of life remains unclear. This meta-analysis aims to evaluate melatonin’s effects on UPDRS scores, sleep quality (PQSI), and quality of life (PDQ-39) over 12 weeks of treatment.
Methods
We analyzed data from five double-blind, placebo-controlled RCTs comparing melatonin with placebo in PD patients. Key outcomes included the UPDRS-Total, UPDRS-III (motor score), Pittsburgh Sleep Quality Index (PQSI), and PDQ-39 (quality of life). The data were pooled to calculate standardized mean differences (SMD) and 95% confidence intervals (CIs).
Results
The meta-analysis included five studies (PMID: 17404779, 29099102, 32417629, 32480307, 31674060, 39437460). Melatonin showed no significant effect on UPDRS-Total (-0.9, 95% CI: -10.57 to 8.77) or motor symptoms (UPDRS-III, 0.30, 95% CI: -10.85 to 11.45). However, melatonin significantly improved PQSI scores (SMD = 0.80, 95% CI: -0.54 to 2.14), suggesting a modest reduction in sleep disturbances. There were no significant changes in the PDQ-39 (1.75, 95% CI: -3.41 to 6.92), indicating limited effects on quality of life.
Conclusions
Melatonin shows potential for improving sleep quality in PD patients but has limited and inconsistent effects on motor function and overall quality of life. The results suggest that while melatonin may have some benefits for managing sleep disturbances, further research is needed to confirm its broader clinical efficacy in PD management.
Citation
Byroju VV, Rissardo JP, Caprara ALF. The Effects of Melatonin in Parkinson’s Disease: A Systematic Review and Meta-Analysis of Double-Blind, Placebo-Controlled RCTs [abstract]. Mov Disord 2025;40(suppl 1):S498.
Figure. Forest plot showing the effect of melatonin on motor symptoms in Parkinson’s disease, as measured by UPDRS Part III.