CU Boulder study: Narcotic painkillers cause chronic pain

Although reports of abuse, addiction and overdoses have long been attached to the misuse of prescription pain medication, researchers at the University of Colorado Boulder may have discovered a new peril.
Results of a three-month study released Monday by the university shows opioids, such as morphine, cause an increase in chronic pain in lab rats, something that could have  implications for people, too.
Peter Grace, a CU Boulder assistant re