The ‘feel-good’ brain chemical that may make tinnitus worse

Serotonin is best known as your body’s “feel-good” chemical. It’s a chemical messenger that helps regulate mood, sleep, appetite and other important functions.

That’s why many common antidepressants are designed to increase serotonin’s availability in the brain. Selective serotonin reuptake inhibitors — better known as SSRIs — work by blocking the brain from reabsorbing serotonin too quickly, leaving more of it available to help nerve cells communicate.

But for some people, medications that boost serotonin may come with an unexpected problem: louder ringing, buzzing, hissing or roaring in the ears.

That condition is tinnitus — the perception of sound when no outside sound is present. And while tinnitus can be mildly annoying for some, for others it can interfere with sleep, concentration, mood and daily life.

For years, researchers suspected serotonin might be involved in tinnitus. But the “how” remained murky.

Now, scientists have identified a specific serotonin-related brain circuit that may help explain why tinnitus sometimes worsens in people taking serotonin-boosting antidepressants.

The serotonin-tinnitus connection

Researchers from Oregon Health & Science University and Anhui University in China studied how serotonin affects the auditory system — the part of the nervous system involved in hearing.

Using a technique called optogenetics, which uses fiber optics and light to activate specific brain cells, the scientists stimulated serotonin-producing neurons in mice.

What happened next was telling.

The stimulation increased activity in a hearing-related region of the brain. The animals also behaved in ways consistent with tinnitus-like perception.

“When you stimulate these serotonergic neurons, we can see that it stimulates activity in the auditory region in the brain,” said Dr. Laurence Trussell, professor of otolaryngology at the OHSU School of Medicine. “We also saw that animals then behaved as if they were hearing tinnitus.”

In other words, increasing activity in this serotonin circuit appeared to make the brain act as though it was hearing a sound that wasn’t there.

That matters because SSRIs — including drugs such as Prozac, Zoloft and similar medications — are designed to increase serotonin signaling.

The study does not prove that SSRIs cause tinnitus in everyone. And it certainly doesn’t mean anyone should stop taking an antidepressant without medical guidance.

But it does help explain why some people report that their tinnitus becomes more intense after starting or changing a medication that affects serotonin.

Why this discovery matters

Tinnitus is complicated. It can be linked to hearing loss, noise exposure, ear injury, medication effects, infections, circulation issues and changes in how the brain processes sound.

But this study gives researchers a clearer map of one possible pathway: a serotonin-driven circuit that connects directly to the auditory system.

That could eventually help scientists develop more targeted medications — ones that preserve serotonin’s benefits for mood while avoiding unwanted effects in hearing-related brain regions.

As Dr. Trussell explained, future treatments may be able to steer serotonin’s effects toward some brain areas and away from others.

That would be a major step forward for people who need help for depression or anxiety, but also struggle with tinnitus.

For now, the takeaway is more practical: If your tinnitus started or worsened after beginning an SSRI or changing your dose, tell your prescribing physician.

Don’t stop the medication on your own. Instead, ask whether your symptoms could be medication-related and whether a different dose, schedule or treatment option might be appropriate.

Other medications linked to tinnitus

SSRIs aren’t the only drugs that have been associated with tinnitus.

A 2022 study led by Brigham and Women’s Hospital found that frequent use of some common pain relievers was linked to a higher risk of persistent tinnitus in women.

In that study, frequent use of moderate-dose aspirin — six to seven days per week — was associated with a 16 percent higher risk of tinnitus in women under 60. Regular use of prescription Cox-2 inhibitors, a type of NSAID, was associated with about a 20 percent higher risk.

Other common NSAIDs and acetaminophen have also been linked with increased tinnitus risk in some research.

That doesn’t mean occasional use is a problem for everyone. But if you’re dealing with ongoing tinnitus, it’s worth reviewing all medications and over-the-counter pain relievers with your doctor or pharmacist.

Blockages and hearing changes can also trigger ringing

Not every case of tinnitus starts in the brain.

Sometimes the problem is much simpler: earwax buildup, fluid from an ear infection, dirt or another blockage in the ear canal.

A blockage can change pressure in the ear and affect how sound signals are processed, triggering or worsening tinnitus.

Hearing loss is another common factor. When the brain receives less sound input from the ears, it may compensate by turning up internal “gain,” making phantom sounds more noticeable.

That’s why anyone with new, one-sided, sudden or worsening tinnitus should consider an evaluation by a healthcare provider or hearing specialist.

What may help you cope with tinnitus

There’s currently no universal cure for tinnitus. But there are ways to reduce how disruptive it feels.

Ask about a hearing evaluation. If you also have hearing loss, hearing aids may help your brain receive more normal sound input. Many people find that when they hear better, they notice tinnitus less.

Use background sound. A fan, white noise machine, calming music or sound therapy app may make tinnitus less noticeable, especially at night.

Track your triggers. Some people notice tinnitus worsens after caffeine, alcohol, poor sleep, stress or loud noise exposure. Keeping a simple symptom journal can help you identify your own patterns.

Protect your ears. Loud noise can worsen tinnitus and hearing loss. Use ear protection around power tools, concerts, firearms, lawn equipment or other high-volume environments.

Consider CoQ10. In one preliminary trial, tinnitus sufferers with low blood CoQ10 levels significantly improved their tinnitus by taking 100 mg of CoQ10 three times per day for 16 weeks. Aging, chronic illness, nutritional deficiencies and cholesterol-lowering medications can lower a person’s CoQ10 levels.

The best first step is not guessing — it’s identifying what may be driving your tinnitus.

Sources:

A discrete serotonergic circuit involved in the generation of tinnitus behavior — PNAS

The brain’s “feel good” chemical may be secretly fueling tinnitus — Science Daily

Frequent use of over-the-counter analgesics associated with risk of tinnitus — Eureka Alert

FAQ: Serotonin and tinnitus