Serotonin Syndrome: How Can You Get Too Much?

Here is an article about Serotonin Syndrome. Is this a case of too much of a good thing? It can easily be misdiagnosed as fibromyalgia or a similar type of chronic fatigue. Some symtoms of serotonin syndrome include mental status changes, behavioral changes, hyperactive nerves and muscles, pain and dysfunction of the autonomic nervous system.
Here is the Journal article