"Serotonin"

Definition: Serotonin is a hormone found in the pineal gland, blood platelets, the digestive tract and the brain. It acts as a chemical messenger, transmitting nerve signals between nerve cells. Fibromyalgia patients have been found to have lower-than-normal levels of serotonin, therefore serotonin-producing medications are frequently used in the treatment of fibromyalgia. Because changes in the levels of serotonin in the brain can alter mood, medications that affect the actions of serotonin are also used in the treatment of depression.