The effect of melatonin on sleep quality and daytime sleepiness in Parkinson's disease: A systematic review and meta-analysis of randomized placebo-controlled trials.
Study Goal
The researchers aimed to determine whether melatonin improves sleep quality and reduces daytime sleepiness in patients with Parkinson's disease (PD).
Results Summary
Melatonin showed modest improvements in sleep quality, particularly with short-term use (4 weeks) of immediate-release formulations at doses >4 mg, but longer-term use (8-12 weeks) and prolonged-release formulations were not significantly effective. The study also noted a slight reduction in daytime sleepiness.
Population
Patients with Parkinson's disease (206 participants across 5 RCTs).
Effective Dosage
≤4 mg (ineffective) vs. >4 mg (effective).
Duration
4 weeks (effective) vs. 8-12 weeks (not significantly effective).
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Melatonin (doses ≤4 mg) | no change | total Pittsburgh Sleep Quality Index (PSQI) scores | patients with PD | MD = -1.26, 95 % CI: -2.72 to 0.20 | showed no significant improvement | #1 |
Melatonin (doses >4 mg) | decrease | total Pittsburgh Sleep Quality Index (PSQI) scores | patients with PD | MD = -2.90, 95 % CI: -4.02 to -1.78 | demonstrated a stronger effect | #2 |
Melatonin (short-term use, 4 weeks) | decrease | PSQI scores | patients with PD | MD = -2.43, 95 % CI: -3.98 to -0.88 | significantly improved | #3 |
Melatonin (longer treatment, 8-12 weeks) | no change | PSQI scores | patients with PD | MD = -1.24, 95 % CI: -3.15 to 0.67 | showed a non-significant effect | #4 |
Melatonin (immediate-release formulations) | decrease | PSQI scores | patients with PD | MD = -2.20, 95 % CI: -3.32 to -1.08 | significantly improved | #5 |
Melatonin (prolonged-release formulations) | no change | PSQI scores | patients with PD | MD = -0.61, 95 % CI: -4.15 to 2.93 | showed no significant effect | #6 |
Melatonin | decrease | excessive daytime sleepiness measured by the Epworth Sleepiness Scale (ESS) | PD patients | MD: -0.97, 95 % CI: -1.81, -0.14 | modestly reduced | #7 |
BACKGROUND: Sleep disturbances are common in Parkinson's disease (PD), significantly impacting quality of life. Melatonin may help, but evidence regarding dosage, formulation, and treatment duration remains inconclusive. OBJECTIVE: To quantitatively analyze the effect of melatonin on sleep quality and daytime sleepiness in patients with PD. METHODS: We comprehensively searched multiple databases up to February 2025, selecting relevant randomized controlled trials (RCTs). RevMan software was used for analysis. Subgroup analyses included treatment duration (4 weeks vs. 8-12 weeks), dose (≤4 mg vs. >4 mg), and formulation (immediate-release vs. prolonged-release). RESULTS: Five RCTs (206 patients) were included. Doses ≤4 mg showed no significant improvement in total Pittsburgh Sleep Quality Index (PSQI) scores (MD = -1.26, 95 % CI: -2.72 to 0.20). Doses >4 mg demonstrated a stronger effect (MD = -2.90, 95 % CI: -4.02 to -1.78). Short-term use (4 weeks) significantly improved PSQI scores (MD = -2.43, 95 % CI: -3.98 to -0.88), whereas longer treatment (8-12 weeks) showed a non-significant effect (MD = -1.24, 95 % CI: -3.15 to 0.67). Immediate-release formulations significantly improved PSQI scores (MD = -2.20, 95 % CI: -3.32 to -1.08), while prolonged-release formulations showed no significant effect (MD = -0.61, 95 % CI: -4.15 to 2.93). Melatonin modestly reduced excessive daytime sleepiness measured by the Epworth Sleepiness Scale (ESS) (MD: -0.97, 95 % CI: -1.81, -0.14). CONCLUSION: Melatonin may improve sleep quality and reduce daytime sleepiness in PD patients, particularly with short-term use of immediate-release formulations.