The overarching aim of this project is to conduct a randomized controlled study to determine whether Mindfulness-Oriented Recovery Enhancement (MORE) vs. a Support Group (SG) can improve pain regulation and hedonic functions (i.e., natural reward responsiveness) thought to be governed by the endogenous opioid system among opioid-treated, chronic, non-neuropathic back pain patients (CNBP) and thereby improve clinical pain, affect, and opioid use.