Scared of the boogeyman? Childhood nightmares linked to cognitive decline, study finds
Everybody has had a bad dream.
Maybe you’re running as fast as you can from a scary monster but you don’t seem to be going anywhere. Maybe you’re falling through the sky and can’t make yourself stop. Maybe you show up to a math exam in your underwear.
No matter your “worst nightmare,” scientists have wondered how bad dreams might play into brain health.
Now, researchers have found a link between those monster-under-the-bed dreams and cognition, starting in childhood.
A new study, published Feb. 26 in The Lancet, says previous research has linked what it calls “distressing dreams” with cognitive impairment in middle-aged and older adults, but research was lacking on how this might start with children.
The study used a prospective birth cohort, which means researchers followed a group of children all born in the United Kingdom during one week in March 1958. At ages 7 and 11, the mothers of the children in the study were asked if their child experienced “bad dreams or night terrors” and how often they occurred.
Their answers were given on a scale of zero to two, zero meaning never and two meaning often.
When those children reached age 50, they began to undergo cognitive testing to see if there were indications that they were experiencing cognitive decline.
Researchers found that children who had persistent bad dreams, and reported having bad dreams at both age markers, had a higher risk of developing a brain disease such as dementia or Parkinson’s later in life.
There are a few possible explanations for the connection.
The first is that bad dreams in children are an “early manifestation of age-related neurodegenerative diseases” such as Parkinson’s, dementia and Alzheimer’s. Those brain diseases occur after degeneration of the right frontal lobe of the brain, the same area responsible for “downregulating negative emotions” during REM sleep.
This would mean that the area of the brain supposed to help you work through negative emotions while sleeping is damaged, and that damage could lead to a more serious disease in the future.
The second possibility is that bad dreams are connected to genetics. The researchers said that previous studies have shown that nightmare frequency is a heritable trait, meaning you get it from your parents. One of the genes that is known to cause more nightmares has also been linked to an increased risk of developing late-onset Alzheimer’s Disease. Having nightmares a lot as a child might mean you have the gene that could cause Alzheimer’s later in life.
The last possibility proposed by the researchers is that when children have lots of nightmares, they aren’t sleeping as well, which doesn’t give the brain time to rest and heal.
Our brains go through a process called glymphatic clearance while we sleep, kind of like the brain taking out the trash. If the brain doesn’t have a chance to rest, the “trash” will pile up and leave proteins that are supposed to be cleared away. This build-up might hurt the brain’s capacity for memory, a key side effect of neurological degenerative diseases.
The researchers suggest if they can confirm one of these possibilities, then “treating distressing dreams during childhood — or preventing them — could become a primary prevention strategy for dementia and [Parkinson’s Disease].”
This story was originally published February 28, 2023 at 12:49 PM with the headline "Scared of the boogeyman? Childhood nightmares linked to cognitive decline, study finds."
