Bad Dreams Could Be An Early Indicator Of Parkinson’s Disease

Bad Dreams Could Be An Early Indicator Of Parkinson’s Disease

Every night before we go to sleep, we spend a few hours in a virtual world generated by our brains, in which we are the main protagonist of an evolving story that we did not create consciously. To put it another way, we daydream.

Dreams are mostly pleasant for most people, occasionally negative, frequently unusual, but seldom terrifying. That is, if they are even recalled. However, about 5% of people experience highly memorable and terrible nightmares (nightmares that cause you to wake up) on a weekly or even nightly basis.

According to recent studies, people with Parkinson’s disease have more terrible dreams and nightmares than people without the disease. Studies suggest that between 17% and 78% of people with Parkinson’s have nightmares weekly.

A study I conducted in 2021 found that people newly diagnosed with Parkinson’s who experience recurring dreams with “aggressive or action-packed” content, have more rapid disease progression in the years following their diagnosis, compared with those without aggressive dreams. As such, my study, alongside similar studies, strongly suggests that the dreams of people with Parkinson’s can predict future health outcomes.

This got me thinking: could dreams of people who don’t have Parkinson’s disease also predict future health outcomes? They can, as my latest study published in The Lancet’s eClinicalMedicine journal demonstrates. Specifically, it demonstrated that experiencing frequent terrible dreams or nightmares in older age could be an early warning indicator of imminent Parkinson’s disease in otherwise healthy persons.

I looked at data from a 12-year study in the United States that included 3,818 older males who were living alone. The guys filled out a variety of questionnaires at the start of the study, one of which asked about terrible nightmares.

Participants who had disturbing nightmares at least once a week were tracked for an average of seven years after the trial ended to see if they were more likely to be diagnosed with Parkinson’s disease.

91 persons were diagnosed with Parkinson’s disease during this time. Those who had frequent terrible nightmares at the start of the trial were twice as likely to acquire Parkinson’s disease as those who only had them once a week.

Surprisingly, a large percentage of diagnoses occurred in the first five years of the study. Those who had frequent terrible nightmares were more than three times as likely to develop Parkinson’s disease throughout this time.

*Years Before*

These findings show that older persons who may be diagnosed with Parkinson’s disease in the future may begin to have disturbing dreams and nightmares a few years before developing the disease’s hallmark symptoms, such as tremors, stiffness, and slowness of movement.

The findings also suggests that our dreams can reveal vital details about our brain anatomy and function, making them a promising subject for neuroscience research.

It’s worth noting, though, that just 16 of the 368 men in this study who had frequent terrible dreams acquired Parkinson’s disease. Because Parkinson’s disease is a relatively uncommon disease, most people who have frequent terrible nightmares are unlikely to develop it.

The finding could be significant for those who have other recognized Parkinson’s risk factors, such as severe daytime sleepiness or constipation. Knowing that frequent terrible dreams and nightmares (especially when they begin suddenly later in life) could be an early sign of Parkinson’s disease could lead to earlier diagnoses and treatment. Doctors may one day be able to act to prevent Parkinson’s disease from ever starting.

My team now intends to investigate the biological underpinnings for dream modifications in Parkinson’s patients using electroencephalography (a technique for measuring brainwaves). This could lead to the discovery of therapies that could treat terrible dreams while also slowing or preventing the onset of Parkinson’s disease in persons at risk.