"Chronic pain sufferers currently taking narcotic pain relievers differ from other chronic pain sufferers as to the severity of their pain, being less likely to have it under control, changing doctors more often, requiring more intensive treatment at hospitals, taking more pills per day, more likely following their doctors prescribed regimen and lastly, to being referred to a specialized program/clinic for their pain."

Source

Roper Starch Worldwide, Inc., "Chronic Pain In America: Roadblocks To Relief," research conducted for the American Pain Society, the American Academy of Pain Medicine and Janssen Pharmaceutica, Jan. 1999.