Sleep deprivation affects how we interpret emotional cues
Insufficient sleep makes it harder to "read" other people
Posted March 2, 2010
Much has been studied about how not getting enough sleep affect one's ability to function. Whether this is expressed in how one performs on tests measuring cognitive abilities, behavior, or even behind the wheel of a driving simulator (and responding worse than some whose blood alcohol levels exceed the legal limit), the results all support the premise that getting enough sleep is crucial if one wants to achieve one's full potential.
Now, a new study published in the March issue of the journal SLEEP* has found that sleep deprivation interferes with people's ability to distinguish between the facial expressions of others, specifically to determine whether they are happy or angry.
In this study, 20 people were deprived of sleep for thirty hours, and then asked to look at photographs of faces, each displaying a different emotional state (happy, sad, and angry) at various levels of intensity. They were then allowed to sleep, and re-tested 24 hours later. The responses from both days were compared, as well as to those of another group of 17 people who served as controls, undergoing the same testing two days in a row without sleep deprivation.
The researchers found that there was a significant blunting in the ability of those who had been tested while sleep deprived to distinguish between angry and happy facial expressions in the moderate intensity range. This difference disappeared after recovery sleep, and was greater in women than in men.
What is the significance of these findings? First, they expose yet another area in which getting enough sleep is critical for normal daily function. One question they raise which I find especially intriguing is what this may mean for children (and adults) with autism, who by definition have difficulties interpreting social cues. It is known that the prevalence of sleep disorders in children with autism is much higher than in the general population, and so one could ask whether the sleep disturbances seen are solely a consequence of the autism, or whether they not only coexist, but also play a role in potentiating (or strengthening) some of autistic features? If that is the case, perhaps we should be more aggressive in treating sleep disorders in this population?
While the numbers in this study were small, it certainly raises many important questions, which will no doubt continue to be looked at going forward.
Dennis Rosen, M.D.
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*van der Helm E; Gujar N; Walker MP. Sleep deprivation impairs the accurate recognition of human emotions. SLEEP 2010;33(3):335-342.