Evidence map›Paper›PMID 34403081›Full record

Trial reportSleep & breathing = Schlaf & Atmung2022

Preliminary finding of a randomized, double-blind, placebo-controlled, crossover study to evaluate the safety and efficacy of 5-hydroxytryptophan on REM sleep behavior disorder in Parkinson's disease.

Mario Meloni, Michela Figorilli, Manolo Carta, Ludovica Tamburrino, Antonino Cannas, Fabrizio Sanna, Giovanni Defazio, Monica Puligheddu

Open access · hybridAbstract readRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in Sleep & breathing = Schlaf & Atmung, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 13 papers, 2 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
13citing papers in PubMed, 2 pooled it
1.6field-weighted citation impact, top 14% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

13 citing papers in PubMed, 2 syntheses or guidelines pooled it, 24 citations in OpenAlex.

  1. Pooled it
  2. Pooled it
  3. Trial
  4. Review
  5. Increased frontal [NPJ Parkinson's disease · 2025
    Article
  6. Article
  7. Article
  8. Article
  9. Review
  10. Review
  11. Article
  12. Review
  13. Current Treatment Options for REM Sleep Behaviour Disorder.Journal of personalized medicine · 2021
    Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors at 1 institution in 1 country.

Mario MeloniDepartment of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy.
Michela FigorilliSleep Disorders Center, Department of Medical Sciences and Public Health, University of Cagliari, Asse Didattico E., SS 554 bivio Sestu, Monserrato, 09042, Cagliari, Italy.
Manolo CartaDepartment of Biomedical Sciences, University of Cagliari, Cagliari, Italy.
Ludovica TamburrinoSleep Disorders Center, Department of Medical Sciences and Public Health, University of Cagliari, Asse Didattico E., SS 554 bivio Sestu, Monserrato, 09042, Cagliari, Italy.
Antonino CannasDepartment of Medical Sciences and Public Health, Neurology Unit, University of Cagliari and AOU Cagliari, Monserrato, Cagliari, Italy.
Fabrizio SannaDepartment of Biomedical Sciences, University of Cagliari, Cagliari, Italy.
Giovanni DefazioDepartment of Medical Sciences and Public Health, Neurology Unit, University of Cagliari and AOU Cagliari, Monserrato, Cagliari, Italy.
Monica PulighedduSleep Disorders Center, Department of Medical Sciences and Public Health, University of Cagliari, Asse Didattico E., SS 554 bivio Sestu, Monserrato, 09042, Cagliari, Italy. puligheddu@unica.it.ORCID 0000-0002-6837-6608
University of Cagliari · IT

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

purposeAltered serotonergic neurotransmission may contribute to the non-motor features commonly associated with Parkinson's disease (PD) such as sleep disorders. The 5-hydroxytryptophan (5-HTP) is the intermediate metabolite of L-tryptophan in the production of serotonin and melatonin. The purpose of this study was to compare the effects of 5-HTP to placebo on REM sleep behavior disorder (RBD) status in patients with PD.

methodsA single-center, randomized, double-blind placebo-controlled crossover trial was performed in a selected population of 18 patients with PD and RBD. The patients received a placebo and 50 mg of 5-HTP daily in a crossover design over a period of 4 weeks.

results5-HTP produced an increase in the total percentage of stage REM sleep without a related increase of RBD episodes, as well as a marginal, non-significant reduction in both arousal index and wake after sleep onset. The self-reported RBD frequency and clinical global impression (CGI) were improved during 5-HTP and placebo treatment in comparison to baseline. 5-HTP significantly improved our patients' motor experiences of daily living as rated by the Unified Parkinson's Disease Rating Scale (UPDRS) part II.

conclusionsThis study provides evidence that 5-HTP is safe and effective in improving sleep stability in PD, contributing to ameliorate patients' global sleep quality. Larger studies with higher doses and longer treatment duration are needed to corroborate these preliminary findings.

Indexed as

Parkinson DiseaseREM Sleep Behavior Disorder5-HydroxytryptophanCross-Over StudiesHumansPolysomnography5-Hydroxytryptophan5-HydroxytryptophanMelatoninParkinson’s diseaseREM sleep behavior disorderSerotonin

Identifiers

PMID34403081
PMCPMC9418091
OpenAlexW3195880973

What OpenQuestion holds

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LicenceCC BY
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Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.