Serotonin affects the perception of pain, helping to “turn down the volume.” It also promotes deep, restful sleep. Studies have found that levels of serotonin may be low or that the neurotransmitter may not be processed effectively in people with fibromyalgia. Decreased levels of serotonin may also lead to a change in the amount of substance P that is released (thus sending pronounced pain messages to the brain) and lower levels of stress hormones.
(Source: Natural Treatments for Fibromyalgia: An A to Z Guide, by Kenna Simmons. An official publication of the Arthritis Foundation. To purchase, visit www.arthritis.org.)