“Placebo Sleep” Can Improve Thinking
The placebo effect works for medicine, exercise, and vision. Now, apparently, it works for sleep. According to a recent study, if people are told they got “above average” quality sleep, they were better at performing cognitive tests.
What Is the Placebo Effect?
The placebo effect is when your brain causes an effect because it believes you are getting a medicine or treatment that should cause that effect. It’s most commonly seen when people are given sugar pills and told they’re medication.
The placebo effect is powerful, and getting stronger. Many drugmakers are struggling to make medications that are stronger than the placebo effect for the conditions they are trying to treat.
Testing Placebo Sleep
To see whether the placebo effect worked for sleep, researchers took a group of 164 subjects and set them up in a fake sleep lab where their sleep could be” monitored” using electrodes. Before going to bed, the subjects were told about the impact of REM sleep on cognition, and that more REM sleep would help them think better. They were told that average sleep consisted of 20-25% REM sleep. In the morning, each subject was asked to rate their sleep, then was told whether the monitoring showed their sleep quality to be below average (about 17% REM sleep) or above average (about 28% REM sleep).
Subjects were then given four tests. On two of the tests–Paced Auditory Serial Addition Test (PASAT, in which people have to add up a series of numbers) and Controlled Oral Word Association Task (COWAT, a verbal fluency test in which people are supposed to think of as many words as possible beginning with a certain letter)–people did better or worse depending on the quality of sleep they’d been told they had. Two other tests–the digit span task (in which people are asked to remember a string of numbers) and the symbol digit modalities test (in which people are asked to match numbers and figures)–were unaffected by sleep ratings. None of the test scores were predicted by self-reported sleep quality.
Better Than Placebo
What to take from this study? Although it certainly seems that there is some significant effect of telling people that they had better quality sleep, the effect seems to be limited. It also reminds us that people aren’t really aware of how well they sleep. First, because people could be fooled by being told they had better or worse sleep, and second, because people’s self-reported sleep quality didn’t correlate with performance.
The placebo effect sure isn’t strong enough to help sleep apnea sufferers (and researchers didn’t even look at its effect on daytime sleepiness, one of the key symptoms of sleep apnea). Fortunately, oral appliance therapy has been shown to be superior to placebo treatment in clinical trials, so we know it really works.
Whether you’re a snorer or have been diagnosed with sleep apnea, we can help you get quality sleep. To learn more, please contact Dr. Lance Timmerman in Seattle for an appointment.
