A new study suggests that a common brain chemical, serotonin, might play a role in causing or worsening tinnitus. Tinnitus is a condition that makes people hear ringing or buzzing sounds in their ears.
Researchers found a direct link between serotonin signals and the auditory system in the brain. This discovery could help millions of people who experience tinnitus.
Serotonin and Tinnitus Connection
Scientists at Oregon Health & Science University and Anhui University in China used mice to study serotonin's effects. They found that higher serotonin levels were linked to more signs of tinnitus in the mice.
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Start Your News DetoxLaurence Trussell, a professor at OHSU, explained that these findings are important for people with tinnitus. He suggests that patients and their doctors should work together to find medications that help with mental health issues like depression and anxiety without making tinnitus worse.
Many antidepressants, called selective serotonin reuptake inhibitors (SSRIs), increase serotonin in the brain. These drugs are widely used for depression and anxiety.
Zheng-Quan Tang from Anhui University noted that while serotonin was suspected in tinnitus, the exact mechanism wasn't clear until now. The study identified a specific brain circuit involving serotonin that directly affects the auditory system and can cause tinnitus-like effects. When this circuit was turned off, the tinnitus symptoms in mice significantly improved.
New Treatment Possibilities
The researchers used a technique called optogenetics, which uses light to activate serotonin-producing neurons in the brain. They then observed how mice reacted using a modified auditory startle test.
Trussell explained that stimulating these serotonin neurons increased activity in the brain's auditory region. The animals then behaved as if they were hearing tinnitus. This matches reports from some patients who say their tinnitus gets worse when they take medications that increase serotonin, including SSRIs.
Trussell believes this research points to a "delicate balance." It might be possible to create new drugs that increase serotonin in specific brain areas but not others. This could allow for the beneficial effects of antidepressants without the potential negative impact on hearing.
Deep Dive & References
A discrete serotonergic circuit involved in the generation of tinnitus behavior - Proceedings of the National Academy of Sciences, 2026
