"Long before it's in the papers"
November 04, 2015


Sleepwalkers feel no pain even when badly injured, study finds

Nov. 4, 2015
Courtesy of the American Academy of Sleep Medicine
and World Science staff

Most sleep­walk­ers feel no pain as they sleep­walk—they just keep sleep­ing, some­times de­spite se­verely in­jur­ing them­selves, a study sug­gests.

Cu­ri­ous­ly, and seem­ingly in con­tra­dic­tion, the re­sults al­so in­di­cat­ed that sleep­walk­ers suf­fer more headaches and mi­graines while awake.

The study sur­veyed peo­ple in­clud­ing 47 sleep­walk­ers who had in­jured them­selves while sleep­walk­ing. Of these, 37 re­ported feel­ing no pain at the time and stay­ing asleep; the oth­er 10 woke up right away in pain.

One pa­tient even jumped out of a third-floor win­dow, suf­fering se­vere frac­tures, but stayed asleep and felt no pain un­til the morn­ing, the re­search­ers said. Anoth­er broke his leg when he climbed on­to the roof and fell down, but did­n’t wake up un­til morn­ing.

“We re­port he­re, for the first time, an an­al­ge­sia phe­nom­e­non as­so­ci­at­ed with sleep­walk­ing,” said prin­ci­pal in­ves­ti­ga­tor Re­gis Lopez, psy­chi­a­trist and sleep med­i­cine spe­cial­ist at Hos­pi­tal Gui-de-Chauliac in Mont­pel­lier, France. The study ap­pears in the No­vem­ber is­sue of the jour­nal Sleep.

In to­tal, Lopez and col­leagues stud­ied 100 non-sleep­walk­ers and 100 pa­tients di­ag­nosed as sleep­walk­ers, in­clud­ing 55 males and 45 fe­males. Sleep­walk­ers had a me­di­an age of 30 years.

De­spite the pain-free nights, re­sults showed that sleep­walk­ers were nearly four times more likely to re­port a his­to­ry of headaches and 10 times more likely to re­port ex­pe­ri­enci mi­graines, af­ter tak­ing in­to ac­count oth­er fac­tors such as in­som­nia and de­pres­sion.

“Our re­sults may help to un­der­stand the mech­a­nisms of the sleep­walk­ing episodes,” said Lopez. “We hy­poth­e­size that a dis­so­ci­ate state of arous­al may mod­i­fy the com­po­nents of sleep-wake be­hav­ior, con­scious­ness, and al­so pain per­cep­tion.”

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Most sleepwalkers feel no pain as they sleepwalk—sometimes despite severely injuring themselves, a study suggests. Curiously, and seemingly in contradiction, the results also indicated that sleepwalkers suffer more headaches and migraines while awake. The study surveyed people including 47 sleepwalkers who had injured themselves while sleepwalking. Of these, 37 reported feeling no pain at the time and staying asleep; the other 10 woke up right away in pain. One patient even jumped out of a third-floor window, suffering severe fractures, but stayed asleep and felt no pain until the morning, the researchers said. Another broke his leg when he climbed onto the roof and fell down, but didn’t wake up until morning. “We report here, for the first time, an analgesia phenomenon associated with sleepwalking,” said principal investigator Regis Lopez, psychiatrist and sleep medicine specialist at Hospital Gui-de-Chauliac in Montpellier, France. The study appears in the November issue of the journal Sleep. In total, Lopez and colleagues studied of 100 non-sleepwalkers and 100 patients diagnosed as sleepwalkers, including 55 males and 45 females. Sleepwalkers had a median age of 30 years. Despite the pain-free nights, results showed that sleepwalkers were nearly four times more likely to report a history of headaches and 10 times more likely to report experiencing migraines, after taking into account other factors such as insomnia and depression. “Our results may help to understand the mechanisms of the sleepwalking episodes,” said Lopez. “We hypothesize that a dissociate state of arousal may modify the components of sleep-wake behavior, consciousness, and also pain perception.”