While the headline mentions the bad news, in truth, this study is hopeful since they were able to restore baseline pain signalling.

CU Boulder study: Narcotic painkillers cause chronic pain • 2016 May 30 • Natalie Munio • The Denver Post

Morphine paradoxically prolongs neuropathic pain in rats by amplifying spinal NLRP3 inflammasome activation • 2016 Apr 19 • Grace et al • PNAS

Using genetic and pharmacological interventions, and innovative Designer Receptor Exclusively Activated by Designer Drugs disruption of microglia reactivity, we demonstrate that opioid-prolonged neuropathic pain arises from spinal microglia and NOD-like receptor protein 3 inflammasome formation/activation. Inhibiting these processes permanently resets amplified pain to basal levels, an effect not previously reported.

Opioid-induced hyperalgesia • Wikipedia