Cannabinoids for Tinnitus?

Recently my wife returned from a night out with a ringing in one ear and significantly diminished hearing. It was a sure sign of injury caused by standing too close to a speaker. She was upset with herself for being so careless and concerned that the condition would persist. For the next couple days, she got extra sleep to aid recovery, and for good measure took an extra dose or two of CBD.

For many other people of all ages, tinnitus is indeed a chronic condition that has nothing to do with loud ‘80s cover bands in small clubs. Risk factors span a wide range of physical and psychological conditions including concussion, smoking, certain medications, ear infection, high blood pressure, anxiety, depression, and, most commonly, age-related hearing loss.

And it’s not just ringing. Technically, tinnitus (pronounced tih-NITE-us or TIN-ih-tus) is the perception of sound originating from within the nervous system that’s unrelated to external stimulation. Tinnitus can also be experienced as buzzing, whirring, humming, whooshing, clicking, and hissing. Whatever the precise nature of the phantom sound, it often comes with a constellation of symptoms related to the disruption such a condition can bring: sleep problems, difficulty concentrating, low mood, etc. Estimates vary, but tens of millions of people in the United States alone likely suffer from chronic tinnitus.

My wife’s ringing tinnitus did fade, and her hearing gradually improved over the course of a few days. The CBD she took may or may not have helped, but according to a recent survey of tinnitus patients, she wasn’t alone in trying — or at least in being interested in cannabis as a potential remedy.

Auditory & Other Symptoms

The survey, whose findings were published in February 2023 in the Journal of Otolaryngology – Head & Neck Surgery1 evaluated cannabis perceptions and consumption among 45 adult tinnitus patients randomly selected and recruited from an outpatient ear, nose, and throat clinic in Ontario, Canada.

Among the 45 respondents, median age 55, only 10 said they were current cannabis users (19 had never used, and 16 had used in the past). But of the 10 current users, eight reported that cannabis did help with some of their tinnitus-related symptoms — if not necessarily the sound itself. Seven of the eight found it helpful for sleep disturbances, seven for pain, six for emotional complaints, four for functional difficulties, and three for dizziness symptoms. Only three of the ten found cannabis helpful for the actual auditory symptoms characterizing tinnitus.

But many more patients were willing to try, perhaps as an indication of the intractability of chronic tinnitus. All but two of the 45 respondents said they’d consider cannabis as a treatment, with 29 seeking help for sleep disturbances, 27 for emotional complaints, 25 for functional disturbances, and nine for pain. Of note, however, 41 of the 45 said they’d turn to cannabis for auditory symptoms — the primary concern for most tinnitus patients yet the least improved by cannabis according to the survey’s 10 current users.

Interestingly, and perhaps unfortunately for patients, previous reviews in 2020 and 20192 also concluded there was insufficient evidence that cannabis can diminish chronic tinnitus.

Mixed Findings

A December 2020 review in the journal Laryngoscope Investigative Otolaryngology3 by researchers at Yale University and nearby University of Connecticut tackles the question head-on. Its title: “Does cannabis alleviate tinnitus? A review of the current literature.”

And its conclusion? “While animal studies have revealed that cannabinoid receptors likely have a role in modulating auditory signaling, there is no compelling data either from animal or human studies for the use of cannabinoids to alleviate tinnitus.”

There could be a role for cannabinoids in the management of tinnitus through their anticonvulsant effects.

In fact, there’s some evidence from animal research that cannabinoid administration may actually induce or exacerbate tinnitus. That’s what appeared to happen in rats injected with the synthetic CB1 agonists WIN55,212‐2 and CP55,940 in a 2010 study4 and THC and CBD in a 1:1 ratio in a 2011 follow-up study.5

As far as human studies, the review authors also summarize two previous surveys in 2010 and 2019, a 1975 clinical trial and a 2006 case study — whose cumulative findings are, at best, entirely unclear.

Despite all this, there is a potential biological rationale for the treatment of tinnitus with cannabinoids, the authors explain. Other animal studies have suggested that cannabinoid receptor expression in the cochlear nucleus may vary with tinnitus symptomatology. And since the most widely accepted hypothesis for the pathophysiology of tinnitus relates to something called “neuronal hyperexcitability” — a mechanism that has also been observed in epilepsy, they note — “there is a potential role of cannabinoids in the management of tinnitus through its anticonvulsant effects.”

Cannabinoid Receptors Influence Hearing

Finally, a November 2020 review in Frontiers in Neurology6 adds more complexity and subtlety to the issue. The article wisely notes that animal studies showing cannabinoids to potentially worsen tinnitus have focused on CB1 agonists. This excludes compounds that target, among others:

CB2 receptors, which influence immune function and are “increasingly recognized as essential in understanding nervous system pathological responses” and “non-classical” cannabinoid targets like TRP (“trip”) channels, which mediate processes including vision, taste, olfaction, touch and hearing.

While the collective evidence to date is mixed and inconclusive, it’s also incomplete. The potential is huge for new animal studies using cannabinoids other than CB1 agonists, and for more robust human studies (indeed any clinical trial at all) to contribute fresh insights to this burning, buzzing question.

Nate Seltenrich, an independent science journalist based in the San Francisco Bay Area, covers a wide range of subjects including environmental health, neuroscience, and pharmacology. Copyright, Project CBD. May not be reprinted without permission.

Footnotes

Mavedatnia, Dorsa et al. “Cannabis use amongst tinnitus patients: consumption patterns and attitudes.” Journal of otolaryngology – head & neck surgery vol. 52,1 19. 24 Feb. 2023, doi:10.1186/s40463-022-00603-8 Zheng, Yiwen, and Paul F Smith. “Cannabinoid drugs: will they relieve or exacerbate tinnitus?.” Current opinion in neurology vol. 32,1 (2019): 131-136. doi:10.1097/WCO.0000000000000631 Narwani, Vishal et al. “Does cannabis alleviate tinnitus? A review of the current literature.” Laryngoscope investigative otolaryngology vol. 5,6 1147-1155. 30 Oct. 2020, doi:10.1002/lio2.479 Zheng, Yiwen et al. “The effects of the synthetic cannabinoid receptor agonists, WIN55,212-2 and CP55,940, on salicylate-induced tinnitus in rats.” Hearing research vol. 268,1-2 (2010): 145-50. doi:10.1016/j.heares.2010.05.015 Zheng, Y et al. “Acoustic trauma that can cause tinnitus impairs impulsive control but not performance accuracy in the 5-choice serial reaction time task in rats.” Neuroscience vol. 180 (2011): 75-84. doi:10.1016/j.neuroscience.2011.02.040 Perin, Paola et al. “Cannabinoids, Inner Ear, Hearing, and Tinnitus: A Neuroimmunological Perspective.” Frontiers in neurology vol. 11 505995. 23 Nov. 2020, doi:10.3389/fneur.2020.505995

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