3.2 Epidemiology
The true incidence of serotonin syndrome remains unknown, and the number of cases is likely significantly higher than reported. The clinical manifestation of serotonin syndrome varies, and its symptoms can resemble those of several other medical conditions. Mild cases are frequently overlooked or dismissed thus making serotonin syndrome likely to be underdiagnosed in clinical practice 1,4,13. At the same time, reported cases of serotonin syndrome appears to be on the rise; likely as a result of the widespread usage of serotonergic medications, in particular selective serotonin reuptake inhibitors (SSRIs) 1,11,13–15.
As a rough estimate, the Toxic Exposure Surveillance System, a major US database, reported 54,410 cases of SSRI poisoning in 2016, with 102 resulting deaths. It is speculated that approximately 15% of these poisonings meet criteria for serotonin syndrome 11.