Melatonin May Improve Sleep in Patients With Parkinson Disease

Melatonin supplementation may improve sleep quality and total sleep time in patients with Parkinson disease (PD), according to findings published in the Journal of Sleep Research.

Sleep disturbances, including insomnia, fragmented sleep, and excessive daytime sleepiness, affect up to two-thirds of patients with PD. Researchers conducted a systematic review and meta-analysis of randomized controlled trials to evaluate the effectiveness of melatonin in treating sleep disorders in this population.

Eight studies involving 409 participants were included in the qualitative review, and 7 were pooled for meta-analysis. Outcomes included the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, rapid eye movement (REM) Sleep Behavior Disorder Screening Questionnaire, and various polysomnographic parameters.

Overall, melatonin was associated with significant improvements in sleep quality (mean difference [MD], –1.75; 95% CI, –2.94 to –0.55; P =.004) and daytime sleepiness (MD, –1.07; 95% CI, –1.87 to –0.27; P =.009) compared with placebo. Sensitivity analyses further strengthened these findings, particularly after the exclusion of 1 heterogeneous study. Melatonin also significantly reduced sleep onset latency (MD, –9.74; 95% CI, –17.47 to –2.02; P =.001) and increased total sleep time (standardized MD, 0.84; 95% CI, 0.47 to 1.21; P <.00001).

However, melatonin had no significant effect on REM Sleep Behavior Disorder Screening Questionnaire, sleep efficiency, REM latency, apnea-hypopnea index, or arousal frequency. Additionally, comparisons between melatonin and clonazepam did not demonstrate a statistically significant difference in daytime sleepiness reduction (MD, –2.65; 95% CI, –5.36 to 0.06; P =.06).

Although statistical improvements were observed, the changes in sleep quality and daytime sleepiness did not meet the thresholds for minimal clinically important differences.

Study limitations include the small sample sizes, heterogeneity in treatment durations and melatonin dosages, and the reliance on subjective sleep metrics.

“Melatonin is a well-tolerated intervention that robustly enhances sleep quality, initiation, and total duration as well as daytime sleepiness,” the study authors concluded.