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Exploding head syndrome (EHS), alternately termed episodic cranial sensory shock,[1] is a benign condition in which a person experiences unreal noises that are loud and short, like a bomb exploding or a gunshot, when falling asleep or waking up.[2][3][4] These noises are often jarring and frightening for the person.[2] Neither the cause nor the mechanism is known.[5] Though harmless in and of themselves, episodes have been known to create distress or impairment in the lives of individuals.[6]

Exploding head syndrome
Classification and external resources
Specialty Sleep medicine



Exploding head syndrome is classified as a parasomnia and a sleep-related dissociative disorder by the 2005 International Classification of Sleep Disorders and is an unusual type of auditory hallucination in that it occurs in people who are not fully awake.[7]


Individuals with exploding head syndrome hear or experience loud imagined noises as they are falling asleep or waking up, have a strong, often frightened emotional reaction to the sound, and do not report significant pain; around 10% of people also experience visual disturbances like perceiving visual static, lightning, or flashes of light. Some people may also experience heat, strange feelings in their torso, or a feeling of electrical tinglings that ascends to the head before the auditory hallucinations occur.[2] With the heightened arousal, people experience distress, confusion, myoclonic jerks, tachycardia, sweating, and the sensation that feels as if they have stopped breathing and have to make a deliberate effort to breathe again.[3][8][9][10]

The pattern of the auditory hallucinations is variable. Some people report having a total of two or four attacks followed by a prolonged or total remission, having attacks over the course of a few weeks or months before the attacks spontaneously disappear, or the attacks may even recur irregularly every few days, weeks, or months for much of a lifetime.[2]

Some individuals mistakenly believe that EHS episodes are not natural events, but are the effects of directed energy weapons which create an auditory effect.[11] Thus, EHS has been worked into conspiracy theories, but there is no scientific evidence that EHS has non-natural origins.


The cause of EHS is unknown,[5] but a number of hypotheses have been put forth (summarized in [2]). The most prevalent theory on the cause of EHS is dysfunction of the reticular formation in the brainstem responsible for transition between waking and sleeping.[2]

Other theories into causes of EHS include:


As of 2018, no clinical trials had been conducted to determine what treatments are safe and effective; a few case reports had been published describing treatment of small numbers of people (two to twelve per report) with clomipramine, flunarizine, nifedipine, topiramate, carbamazepine, methylphenidate.[2] Studies suggest that education and reassurance can reduce the frequency of EHS episodes.[3] There is some evidence that individuals with EHS rarely report episodes to medical professionals.[10]


There have not been sufficient studies conducted to make conclusive statements about prevalence nor who tends to suffer EHS.[2] One study found that 13.5% of a sample of undergrads reported at least one episode over the course of their lives, with higher rates in those also suffering from sleep paralysis.[6]


Case reports of EHS have been published since at least 1876, which Silas Weir Mitchell described as "sensory discharges" in a patient.[6] However, it has been suggested that the earliest written account of EHS was described in the biography of the French philosopher René Descartes in 1691.[12] The phrase "snapping of the brain" was coined in 1920 by the British physician and psychiatrist Robert Armstrong-Jones.[6] A detailed description of the syndrome and the name "exploding head syndrome" was given by British neurologist John M. S. Pearce in 1989.[13] More recently, Peter Goadsby and Brian Sharpless have proposed renaming EHS "episodic cranial sensory shock"[1] as it describes the symptoms more accurately (including the non-auditory elements) and better attributes to Mitchell.


  1. ^ a b Goadsby, Peter J.; Sharpless, Brian A. (2016-11-01). "Exploding head syndrome, snapping of the brain or episodic cranial sensory shock?". J Neurol Neurosurg Psychiatry. 87 (11): 1259–1260. doi:10.1136/jnnp-2015-312617. ISSN 0022-3050. PMID 26833175. 
  2. ^ a b c d e f g h i j k l Sharpless, Brian A. (December 2014). "Exploding head syndrome". Sleep Medicine Reviews. 18 (6): 489–493. doi:10.1016/j.smrv.2014.03.001. PMID 24703829. 
  3. ^ a b c Frese, A.; Summ, O.; Evers, S. (6 June 2014). "Exploding head syndrome: Six new cases and review of the literature". Cephalalgia. 34 (10): 823–827. doi:10.1177/0333102414536059. PMID 24907167. 
  4. ^ a b c "Exploding Head Syndrome - American Sleep Association". Retrieved 2015-11-28. 
  5. ^ a b Blom JD (2015). "Auditory hallucinations". Handb Clin Neurol. 129: 433–55. doi:10.1016/B978-0-444-62630-1.00024-X. PMID 25726283. 
  6. ^ a b c d Sharpless BA (2015). "Exploding head syndrome is common in college students". J Sleep Res. 24: 447–9. doi:10.1111/jsr.12292. PMID 25773787. 
  7. ^ Thorpy, Michael J. (2012-10-01). "Classification of Sleep Disorders". Neurotherapeutics. 9 (4): 687–701. doi:10.1007/s13311-012-0145-6. ISSN 1933-7213. PMC 3480567 . PMID 22976557. 
  8. ^ Blom, Jan Dirk (2009-12-08). A Dictionary of Hallucinations. Springer Science & Business Media. ISBN 9781441912237. 
  9. ^ Larner, Andrew J.; Coles, Alasdair J.; Scolding, Neil J.; Barker, Roger A. (2011-01-19). A-Z of Neurological Practice: A Guide to Clinical Neurology. Springer Science & Business Media. ISBN 9781848829947. 
  10. ^ a b Sharpless, Brian A (2017-04-06). "Characteristic symptoms and associated features of exploding head syndrome in undergraduates". Cephalalgia. doi:10.1177/0333102417702128. 
  11. ^ A.,, Sharpless, Brian. Unusual and rare psychological disorders : a handbook for clinical practice and research. ISBN 9780190245863. OCLC 952152912. 
  12. ^ Otaiku AI (2018). "Did René Descartes have Exploding Head Syndrome?". J Clin Sleep Med. 14 (4): 675–8. doi:10.5664/jcsm.7068. PMC 5886445 . PMID 29609724. 
  13. ^ Thorpy MJ, Plazzi G (2010). The Parasomnias and Other Sleep-Related Movement Disorders. Cambridge University Press. p. 231. ISBN 0-521-11157-9. Retrieved 2011-03-18. 

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