Comorbidity of fibromyalgia and depression?

Highly Associated. To my mind, the explanation is that chronic pain of the musculoskeletal system worsens as the fibromyalgia sufferer lays on the sleep surface. Ground forces of the sleep surface stress painful joints, ligaments, tendons, & muscles. Neurologists well know that interrupted and unrefreshing sleep leads to daytime fatigue and depression.
Fibro & depression. About 3 in 10 people with fibromyalgia also have major depression at the time of their diagnosis. Also though some have suggested that fibromyalgia is "just depression, " they are not equivalent. http://www.webmd.com/fibromyalgia/guide/fibromyalgia-and-depression.