A recent article published in eClinical Medicine proposed that the onset of nightmares or distressing dreams in older adults was associated with the early signs of Parkinson′s disease. Mr. Abidemi Otaiku, BMBS, NIHR educational medical fellow in neurology, University of Birmingham, and uniqueness registrar in neurology at Birmingham City Hospital, United Kingdom, stated that the older individuals experiencing any change in their dreams, without a known trigger should seek medical help.

In the study, at baseline, the incident PD group was more likely to experience depression and develop insomnia. The adjusted logistic regression model showed that individuals with distressing dreams have a twofold increased risk of developing PD (odds ratio [OR], 2.01). A separate evaluation dividing the follow-up length into segments confirmed that distressing dreams were linked with a threefold increase in PD incidence rate during the first 5 years at baseline (OR, 3.38). 

However, the PD incidence rate for the following 7 years was not very significant (OR, 1.55). Hence, the study author concluded that the distressing dreams can be a prodromal symptom of PD, even in people with normal cognition and who aren′t depressed.

(Source: https://www.medscape.com/viewarticle/976032#vp2 )