1, 2. Serotonin and Dopamine
People often group serotonin and dopamine together. Serotonin has been heavily linked to depression and a variety of other mood disorders. Likewise, dopamine is also believed to be connected to mood. It functions as part of the reward-motivated behavior section in your brain, and people believe that it plays a part in pain management.
For people with fibromyalgia, both of these hormones help with mood and pain management. When a person is happier, that person is not as focused on pain. There have been a few studies that show that the serotonin pathways in a person with fibromyalgia have a decreased flux. This means that the individuals are not getting as much serotonin, which can severely affect their mood and pain levels. Similarly, some studies have shown that some people with fibromyalgia have a different dopamine response to pain than healthy people do.