Does serotonin play a role in tinnitus? Mouse study raises question

• New research in mice suggests that higher levels of serotonin might worsen the symptoms of tinnitus, a condition where a person hears constant buzzing or ringing in one or both ears.
• Tinnitus can severely impact mental well-being, causing or exacerbating symptoms of depression and anxiety.
• Since psychiatrists often treat clinical depression and anxiety with serotonin-increasing medication, the study finding is posing an important question about how best to manage tinnitus when it co-occurs with mental health conditions.
• Practicing psychiatrists and tinnitus experts, however, advise that the finding ought to be treated with caution.

According to the latest available estimates, 14% of adults around the world experience tinnitus, a condition characterized by the perception of constant ringing or buzzing in one or both ears.

Due to its nature, this condition can severely impact quality of life, including mental health, and it may cause symptoms of anxiety and depression.

There is also anecdotal evidence that tinnitus is fairly common in attention deficit hyperactivity disorder (ADHD), exacerbating problems with focus as well as anxiety.

Given all of this, the findings of a study on tinnitus conducted by researchers from Oregon Health & Science University (OHSU) in the United States and Anhui University in China, and recently published in PNAS may not spell good news.

The study, conducted in mice, found that higher levels of serotonin, a neurotransmitter or chemical messenger that plays key roles in emotional regulation, appeared to exacerbate behavioral responses associated with worsening tinnitus symptoms, such as becoming more easily startled by noises.

If confirmed in humans, this finding may pose certain problems for the treatment and management of anxiety and depression in people who also experience tinnitus.

This is because treatment plans for these two mental health conditions often involve taking selective serotonin reuptake inhibitors (SSRIs), a form of medication that aims to boost serotonin levels.