Your nightmares could be a warning of future disease

In the early ‘80s, creators dreamed up an unnamed horror anthology series intended for broadcast in 1983. Four episodes were shot, but the deal fell through. That dream instead became an anthology film called Nightmares, made up of four standalone stories, each based on a different urban legend.

Indeed, there’s something enthralling about nightmares, the ways in which our minds invent private horrors for which we are the only audience. It’s unclear precisely why we have nightmares or what purpose they might serve to our semiconscious minds. However, there is new evidence that they may provide insight into our overall health and could even be an early warning of a looming disease diagnosis.

Dr. Abidemi Otaiku from the Centre for Human Brain Health at the University of Birmingham investigated the connection between nightmares and Parkinson’s disease. He found that a higher-than-normal frequency of nightmares correlates to a greater risk of developing Parkinson’s. The findings of the study were published in the journal eClinicalMedicine.

Previous research found that 81% of diagnosed Parkinson’s patients report frequent, intense, and vivid bad dreams in the time shortly after diagnosis. The frequency of their nightmares is significantly higher than the overall adult population. Dr. Otaiku wondered if the increase in bad dreams might precede physical symptoms and serve as a warning of the disease.

To find out, Dr. Otaiku reviewed health survey data from 3818 men aged 67 years old or older, taken over a 12-year period. At baseline, none of the study participants had been diagnosed with Parkinson’s and they were asked, among other things, to self-report on the frequency of nightmares they had experienced over the previous month.

Over the course of the follow up period, 91 cases of Parkinson’s disease were diagnosed, and a review of the survey results confirmed that those individuals who reported a higher-than-normal rate of nightmares were more likely to develop the disease over the next five years. Overall, people who reported frequent nightmares — occurring at least once a week — were at least twice as likely to be diagnosed with Parkinson’s in the following five years. By some measures, the effect was greater than three times as likely.

After five years, the effect fell away, suggesting that increased nightmares emerge within approximately a five-year period prior to the onset of physical symptoms. Other factors which appeared related to the frequency of nightmares were lower education, poor physical or mental health, lower alcohol consumption, and lower physical activity. So, if you’re having nightmares, going for a jog and having a nightcap might help to settle your mind.

Research indicates that in those patients who have developed Parkinson’s disease, changes in the right frontal lob may be to blame for their nightmares. The emergence of nightmares in advance of a diagnosis may point to subtle changes in that area of the brain which aren’t yet detectable by tests. Those changes could impair a person’s ability to regulate negative emotions during REM sleep resulting in nightmares and, as the changes progress, physical Parkinson’s symptoms.

If you’re having frequent bad dreams, however, it’s likely not a cause for concern. In the study, the relationship between nightmares and Parkinson’s was not one-to-one. While 91 cases of Parkinson’s disease were diagnosed from the sample population, 368 participants reported frequent bad dreams at onset. Which is to say, Parkinson’s appears to cause an increase in nightmares, but nightmares are not necessarily indicative of the disease. Sometimes a bad dream is just a bad dream, even if they happen more often than you’d like.