Are Vivid Dreams a Symptom of Disease?: An Emerging Connection

Growing evidence suggests that vivid dreams and nightmares may be associated with certain disease states. Emerging research indicates that changes in dreaming patterns—particularly vivid dreams and dream enactment—can precede the development of neurological conditions by many years. Below is a closer look at one of the most well-studied associations.

It’s about Parkinson’s Disease

For the purposes of this discussion, the term Parkinson’s disease (PD) will be used as an umbrella that includes Parkinson’s disease, Parkinsonism, and Lewy body dementia. Vivid dreams and nightmares can be an early symptom of PD and, in some cases, may begin many years, even decades before any classic motor symptoms of this neurodegenerative condition appear.

One particularly important phenomenon is dream enactment, which occurs when a person physically acts out their dreams while asleep. For example, someone dreaming of being chased may move their arms and legs as if running, despite remaining fully asleep. Dream enactment is a hallmark feature of isolated REM sleep behavior disorder (iRBD)and is strongly associated with Parkinson’s disease.

A 2019 meta-analysis that followed approximately 4,000 patients with iRBD found that one-third went on to develop Parkinson’s disease or dementia with Lewy bodies within an average of five years after the onset of dream enactment. Statistical modeling from this analysis estimated that by 14 years, up to 90% of individuals with persistent dream enactment would develop Parkinson’s disease.¹

More recently, a study published in 2025 used advanced brain MRI techniques to evaluate the substantia nigra, the region of the brain affected in Parkinson’s disease and responsible for many of its characteristic movement symptoms, such as tremor and freezing of gait. When researchers compared individuals with iRBD to healthy controls and patients with established Parkinson’s disease, they found that iron levels in the substanta nigra were elevated in those with iRBD—higher than healthy controls but lower than those with Parkinson’s disease.²

Over a four-year follow-up period, iron deposition in the substantia nigra continued to increase in individuals with iRBD, progressively approaching the levels seen in patients with Parkinson’s disease.² These findings further support the concept that sleep-related dream changes may represent an early, measurable stage in the development of Parkinson’s disease.

A genetics study published in 2025 compared patients with Parkinson’s disease with and without dream enactment. In this study, dream enactment was not classified as isolated REM sleep behavior disorder (iRBD), since the diagnosis of Parkinson’s disease means the condition is no longer considered isolated. The study identified two genes—SNCA and LRRK2—as being pivotal in patients with Parkinson’s disease who experience dream enactment.³

Additionally, a 2023 review found that when REM sleep behavior disorder or dream enactment is present in Parkinson’s disease, the disease tends to progress more rapidly and with greater severity. Patients with dream enactment had higher rates of cognitive decline, depression, hallucinations, and anxiety compared with those without these sleep-related symptoms.⁴

Considering the strong evidence, physicians should not ignore a patient’s concern about vivid dreams and nightmares, especially when sleep enactment is present.

References:

1. https://www.sciencedirect.com/science/article/abs/pii/S1087079218300819?via%3Dihub

Galbiati A, Verga L, Giora E, Zucconi M, Ferini-Strambi L. The risk of neurodegeneration in REM sleep behavior disorder: A systematic review and meta-analysis of longitudinal studies. Sleep Med Rev. 2019 Feb;43:37-46. doi: 10.1016/j.smrv.2018.09.008. Epub 2018 Nov 8. PMID: 30503716.

2. https://academic.oup.com/braincomms/article/7/3/fcaf212/8155332?login=false

Gaurav R, Lejeune FX, Santin MD, Valabrègue R, Pérot JB, Pyatigorskaya N, Mangone G, Leu-Semenescu S, Villain N, Habert MO, Vidailhet M, Arnulf I, Corvol JC, Lehéricy S. Early brain iron changes in Parkinson's disease and isolated rapid eye movement sleep behaviour disorder: a four-year longitudinal multimodal quantitative MRI study. Brain Commun. 2025 Jun 2;7(3):fcaf212. doi: 10.1093/braincomms/fcaf212. PMID: 40585816; PMCID: PMC12203178.

3. https://www.nature.com/articles/s41531-025-01078-w

Sosero YL, Heilbron K, Fontanillas P, Norcliffe-Kaufmann L, Yu E, Rudakou U, Ruskey JA, Freeman K, Asayesh F, Brolin KA, Swanberg M, Morris HR, Wu L, Real R, Pihlstrøm L, Tan M, Gasser T, Brockmann K, Liu H, Hu MTM, Grosset DG, Lewis SJG, Kwok JB, Pastor P, Alvarez I, Skorvanek M, Lackova A, Ostrozovicova M, Rizig M; 23andMe Research Team; International Parkinson’s Disease Genomics Consortium; Krohn L, Gan-Or Z. Genome-wide association study of REM sleep behavior disorder in Parkinson's disease. NPJ Parkinsons Dis. 2025 Sep 25;11(1):272. doi: 10.1038/s41531-025-01078-w. PMID: 40998812; PMCID: PMC12462436.

4. https://www.nature.com/articles/s41419-023-05672-9

Calabresi P, Mechelli A, Natale G, Volpicelli-Daley L, Di Lazzaro G, Ghiglieri V. Alpha-synuclein in Parkinson's disease and other synucleinopathies: from overt neurodegeneration back to early synaptic dysfunction. Cell Death Dis. 2023 Mar 1;14(3):176. doi: 10.1038/s41419-023-05672-9. PMID: 36859484; PMCID: PMC9977911.