title: Endogenous Opioid Function and Responses to Morphine: The Moderating Effects of Anger Expressiveness.
abstract: Long-term use of opioid analgesics may be ineffective or associated with significant negative side effects for some people. At present, there is no sound method of identifying optimal opioid candidates. Individuals with chronic low back pain (n = 89) and healthy control individuals (n = 102) underwent ischemic pain induction with placebo, opioid blockade (naloxone), and morphine in counterbalanced order. They completed the Spielberger Anger-Out subscale. Endogenous opioid function × Anger-out × Pain status (chronic pain, healthy control) interactions were tested for morphine responses to ischemic threshold, tolerance, and pain intensity (McGill Sensory and Affective subscales) and side effects. For individuals with chronic pain and healthy control participants, those with low endogenous opioid function and low anger-out scores exhibited the largest morphine analgesic responses, whereas those with high anger-out and low endogenous opioid function showed relatively weaker morphine analgesic responses. Further, individuals with chronic pain with low endogenous opioid function and low anger-out scores also reported the fewest negative effects to morphine, whereas those with low endogenous opioid function and high anger-out reported the most. Findings point toward individuals with chronic pain who may strike a favorable balance of good analgesia with few side effects, as well as those who have an unfavorable balance of poor analgesia and many side effects.
  
  
  
  We sought to identify optimal candidates for opioid pain management. Low back pain patients who express anger and also have deficient endogenous opioid function may be poor candidates for opioid therapy. In contrast, low back patients who tend not to express anger and who also have deficient endogenous opioid function may make optimal candidates for opioid therapy.
authors.affiliation: Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois. Electronic address: John_burns@rush.edu.
authors.forename: John W
authors.initials: JW
authors.lastname: Burns
authors.affiliation: Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Stephen
authors.initials: S
authors.lastname: Bruehl
authors.affiliation: Department of Psychology, Ohio University, Athens, Ohio.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: France
authors.affiliation: Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois.
authors.forename: Erik
authors.initials: E
authors.lastname: Schuster
authors.affiliation: Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois.
authors.forename: Daria
authors.initials: D
authors.lastname: Orlowska
authors.affiliation: Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Melissa
authors.initials: M
authors.lastname: Chont
authors.affiliation: Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Rajnish K
authors.initials: RK
authors.lastname: Gupta
authors.affiliation: Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois.
authors.forename: Asokumar
authors.initials: A
authors.lastname: Buvanendran
mesh_terms: D000293:Adolescent; D000328:Adult; D000701:Analgesics, Opioid / Q000009:adverse effects* / Q000378:metabolism*; D000786:Anger / Q000502:physiology*; D059350:Chronic Pain / Q000188:drug therapy; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D017116:Low Back Pain / Q000188:drug therapy* / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000009:adverse effects*; D009270:Naloxone / Q000627:therapeutic use; D009292:Narcotic Antagonists / Q000627:therapeutic use; D010147:Pain Measurement; D017288:Pain Threshold; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D009270:Naloxone; D009020:Morphine
keywords: Endogenous opioid function; anger-out; morphine analgesic responses; side effects