Tinnitus is the experience of a sound which is usually described as a ringing, humming, buzzing, roaring, hissing, or clicking that occurs when no corresponding external sound is present.   This sound can be quiet or loud in volume, low or high in pitch, and can sound as if it is coming from either both ears, one ear, or from an internal location within the head itself. At higher levels of intensity or with prolonged persistence, tinnitus can significantly interfere with a person's concentration in a manner that is distinctly uncomfortable and associated with increased anxiety or depression.
Tinnitus is a relatively common experience that regularly affects around 5-10% of the population.  Within the context of psychoactive substance usage, however, it can occur under the influence of a wide variety of compounds such DMT, 5-MeO-DMT, nitrous oxide, aspirin, tricyclic antidepressants, and buproprion. It can also occur under the influence of benzodiazepine withdrawals, sleep deprivation, and stimulant comedowns.
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- "Tinnitus". NIH – National Institute on Deafness and Other Communication Disorders (NIDCD). | https://web.archive.org/web/20190403204320/https://www.nidcd.nih.gov/health/tinnitus
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