Could serotonin — the brain's “feel-good” chemical — play a role in tinnitus?
A May 2026 study in the journal PNAS found that raising serotonin in one specific brain circuit made tinnitus-like signals worse in mice — and quieting that circuit eased them.
Researchers at Oregon Health & Science University and Anhui University used light-based tools (a technique called optogenetics) to switch a serotonin circuit in the brain on and off in mice. When they turned that circuit up, the animals showed more tinnitus-like behavior. When they turned it down, the signs eased.
Why it may matter to you: Serotonin is the same brain chemical that many antidepressants (SSRIs) raise. The researchers suggest this could help explain why a small number of people notice their tinnitus gets louder after starting an SSRI. If that has been your experience, it is worth an honest conversation with your prescriber — not a reason to change or stop any medication on your own.
Keep it in perspective: This was a study in mice, not people, and it points toward possible future treatments rather than one that exists today. It is a promising clue about how tinnitus works — not a cure, and not medical advice.