Doctors Identified Risk Factors for a Potentially Violent Sleep Disorder

In Nightmare on Elm Street, the teenager haunted by Freddy Krueger shows signs of REM sleep behavior disorder, a condition that’s scary enough in that fantasy world, but is perhaps almost as worrisome in real life. RBD is a somewhat mysterious condition that makes people act out their dreams. In this state, they can engage not only in relatively harmless behavior such as walking around or eating but also potentially dangerous behavior, like punching or kicking. The root causes of this strange condition have long eluded doctors, but new research in the journal Neurology sheds some light on the potential risk factors for RBD.

In a paper published on Wednesday, a team of researchers at McGill University in Montreal combed through data from more than 30,000 Canadians to find what lifestyle or demographic factors could contribute to RBD. In addition to confirming what past research has found, that some groups are at higher risk — males, smokers, and people with lower education levels — the team also identified a couple of previously underexamined risk factors: alcohol use and psychological distress.

While most sleepers’ muscles go limp during the REM — rapid eye movement — stage of sleep, during which dreams usually occur, people with RBD do the opposite. In some cases, as in the famous case of comedian Mike Birbiglia who jumped through a window in his sleep, the disorder can be extremely dangerous.

The new study, in which researchers identified 958 potential cases of RBD from 30,097 people between 45 and 85 who are part of the Canadian Longitudinal Study on Aging, begins to fill in the gaps in doctors’ understanding about the condition.

“While much is still unknown about REM sleep behavior disorder, it can be caused by medications or it may be an early sign of another neurologic condition like Parkinson’s disease, dementia with Lewy bodies or multiple system atrophy,” Ronald Postuma, M.D. a neurology researcher at McGill University and one of the study’s co-authors, said on Wednesday. “Identifying lifestyle and personal risk factors linked to this sleep disorder may lead to finding ways to reduce the chances of developing it.”

Specifically, the two new factors Postuma and his team identified indicate that for some people, RBD is imminently treatable. While alcohol use and psychological distress aren’t necessarily the easiest elements to cut out of one’s life, treating these risk factors for RBD seems like a small price to pay for relief from the condition.

Helping to treat RBD is a big deal for people affected by it since it’s not just a troublesome condition, it’s also a potential warning of future illnesses like Parkinson’s disease.

“Our research does not show that these risk factors cause REM sleep behavior disorder, it only shows they are linked,” said Postuma. “Our hope is that our findings will help guide future research, especially because REM sleep behavior disorder is such a strong sign of future neurodegenerative disease. The more we understand about REM sleep behavior disorder, the better positioned we will be to eventually prevent neurologic conditions like Parkinson’s disease.”