What is exploding head syndrome (EHS), and should you be concerned about it if you’re consuming cannabis?
Exploding head syndrome is a sensory sleep disorder associated with hearing loud explosion-like sounds during different stages of sleep cycles.  These sounds last less than a second and are not typically painful, but they can occur along with flashes of light and cause a great deal of unrest in those who experience them. Signs of EHS were first documented in 1876, but “it was not classified as a sleep disorder until 2005,” and just recently is starting to be referred to as “cranial shock.” 
So where does cannabis come into the picture? The April 2020 issue of Sleep, the official publication of the Sleep Research Society, included a case report claiming to be “the first report to link [cannabis] use with the occurrence of EHS.”  The case only included one patient, a 45-year-old male who reported EHS like symptoms accompanied with visual hallucinations, panic, and vertigo. The patient told researchers he had been consuming cannabis three times daily for 24 years. He was then prescribed the antidepressant mirtazapine and discontinued his use of cannabis as well as prescription clonazepam (an anti-anxiety medication).
After these changes, all of his symptoms improved until the next time he consumed cannabis, which was followed that night by a return of his EHS. He discontinued his cannabis use again, only to have the EHS symptoms return once more, again after consuming cannabis. The doctors then used this one example to consider a potential link between cannabinoids and EHS. They note that “[t]he etiology of EHS remains elusive.”
To answer the main question we started with, no you shouldn’t necessarily be worried about EHS being a side effect of cannabis. Reports are limited to this one case study looking at only one patient, who was also diagnosed with depression, anxiety, multi-substance abuse, and two years of neuropsychiatric symptoms. The American Sleep Association says scientists estimate EHS affects 10% of people. So, there is a slim chance you could experience symptoms of EHS at some point in your life, but an even slimmer chance that the symptoms will be side effects from cannabis.
- Khan I, Slowik JM. Exploding head syndrome. StatPearls [Internet]. Treasure Island, Fl: StatPearls Publishing; 2021. https://www.ncbi.nlm.nih.gov/books/NBK560817/
- Missak C, et al. 1239 Mind blown: exploding head syndrome as a side effect of marijuana. Sleep. 2020;43(1):A472 – A473. https://academic.oup.com/sleep/article-abstract/43/Supplement_1/A472/5846843. Times Cited: n/a; Journal Impact Factor: 5.823