New research shows that serotonin, a brain chemical boosted by many antidepressants, can intensify tinnitus. Scientists identified a specific brain circuit in mice that links higher serotonin levels to behaviors mimicking the ringing condition.
A team from Oregon Health & Science University and Anhui University in China published the findings in the Proceedings of the National Academy of Sciences. They used optogenetics to stimulate serotonin-producing neurons and observed increased activity in auditory brain regions, along with tinnitus-like responses in the mice via a modified startle test. The study builds on earlier work from 2017 and matches reports from some patients whose tinnitus worsens on SSRIs.