Do Frequent Nightmares Presage Parkinson's Disease?
In a recent study in EClinicalMedicine, an online publication from the Lancet family of journals, investigators observed older individuals experiencing bad dreams and nightmares showed a greater risk for subsequent onset of Parkinson’s Disease.
In one way, this observation is not surprising as it has been described for almost two decades that a nightmarish condition known as REM Behavior Disorder (RBD) frequently precedes the onset of Parkinson’s. In RBD, nightmares are not only highly distressing but also highly active as the individual literally acts out the dreams with lots of body motion. Injury to self or others is common in RBD.
However, in the study just published, the authors only captured information on the prevalence of bad dreams. They did not seem to have acquired other detailed information to know whether some nightmare sufferers also had RBD symptoms.
Nevertheless in their Discussion, they mention the problem of RBD, but they seemed to highlight their sample only contained those with nightmares and no other symptoms. If so, then the new info here is that “straightforward” distressing dreams in the elderly are a risk factor for Parkinson’s, independent of RBD.
A lot more research is needed to confirm or reject this hypothesis.