Chronic Low Back Pain Associated with Depression and Fatigue.
A survey of over 500 chronic low back pain patients who have been on work disability for between two and ten months shows that 69.7% report experiencing substantial fatigue as well. Those reporting fatigue are more likely to suffer from depressive symptoms and are also more likely to still be in pain 3, 6, and 12 months after completing their initial survey.
Pain Medicine, April 2014