Fibromyalgia is a common syndrome in which a person has long-term, body-wide pain and tenderness in the joints, muscles, tendons, and other soft tissues. Fibromyalgia has also been linked to fatigue, sleep problems, migraines, depression, and anxiety disorders. Small baseline studies have shown that in comparison to the placebo group, those who were given THC were less accurate at identifying negative emotions and showed no loss in accuracy with respect to the faces with positive emotions. MRI testing has shed some light on why this occurs; THC decreased brain activity in response to the negative stimuli, but not for positive stimuli. Simply put the study eludes that if THC is shown to have an effect on the negative bias, it could prove useful in the treatment of depression. This bears up a large amount of anecdotal evidence that people suffering from fibromyalgia, neuropathy and rheumatoid arthritis experience relief from plant derived cannabis THC.