Endogenous opioids may buffer effects of anger arousal on sensitivity to subsequent pain

Abstract

Evidence suggests that anger and pain are related, yet it is not clear by what mechanisms anger may influence pain. We have proposed that effects of anger states and traits on pain sensitivity are partly opioid-mediated. In this study, we tested the extent to which analgesic effects of acute anger arousal on subsequent pain sensitivity were opioid-mediated by subjecting healthy participants to anger-induction and pain either under opioid blockade (oral naltrexone) or placebo. Participants were 160 healthy individuals. A double-blind, placebo-controlled, between-subjects opioid blockade design was used, with participants assigned randomly to one of two Drug conditions (placebo or naltrexone), and to one of two Task Orders (anger-induction followed by pain or vice versa). Results of ANOVAs showed significant Drug Condition × Task Order interactions for sensory pain ratings (MPQ-Sensory) and angry and nervous affect during pain-induction, such that participants who underwent anger-induction prior to pain while under opioid blockade (naltrexone) reported more pain, and anger and nervousness than those who underwent the tasks in the same order, but did so on placebo. Results suggest that for people with intact opioid systems, acute anger arousal may trigger endogenous opioid release that reduces subsequent responsiveness to pain. Conversely, impaired endogenous opioid function, such as that found among some chronic pain patients, may leave certain people without optimal buffering from the otherwise hyperalgesic affects of anger arousal, and so may lead to greater pain and suffering following upsetting or angry events.

Reduction of conditioned pain modulation in humans by naltrexone: an exploratory study of the effects of pain catastrophizing

“…A disadvantage of naltrexone is that it is difficult to dose by body weight; therefore, we administered 50 mg in order to achieve adequate blockade in the vast majority of subjects. Most experimental studies have used this dose to evaluate physiological and subjective responses to a cold pressor task (al'Absi et al, 2004; Kotlyar et al, 2008) and other pain studies (Burns et al, 2009) without any discussion of possible weight issues, nor did they control for BMI. In addition, we did not include a condition to evaluate the effects of repeated heat pain trials in the absence of water immersion with naltrexone, which may reduce the ability to determine the full impact of the endogenous opioids on pain inhibition since naltrexone could influence the intensity of heat pain particularly over repeated trials.…”

Anger regulation style, anger arousal and acute pain sensitivity: evidence for an endogenous opioid “triggering” model

“…This sample was comprised of 146 of the 198 individuals who participated in the larger study (described in Burns et al, 2009). Given the focus of the current study on adaptation to pain over the duration of the ischemic task, the current sample included all participants who tolerated the ischemic pain task for at least 4 min.…”

“…Scores on the Anger-out Subscale of the Anger Expression Inventory (Spielberger et al, 1985)—as well as the Anger-in Subscale and negative affect control variables (see below)—were used as continuous variables in analyses. The present study is based on data collected for a previous study (Burns, Bruehl, Chung, Magid, Chont, Goodlad, Gilliam, Matsuura, & Somar, 2009), in which only the effects of Drug × Task Order were examined for pain ratings recorded at the end of the pain stimulus. Here, we examined the degree to which anger regulation style, anger arousal, and endogenous opioids exerted effects on changes in pain severity (i.e., adaptation over time) during an ongoing pain stimulus.…”

Hypoalgesia associated with elevated resting blood pressure: evidence for endogenous opioid involvement

“…Data presented in this study were obtained as part of a project examining opioid mechanisms underlying analgesia related to anger arousal (see Burns et al 2009 for details). A double-blind, placebo-controlled, between-subjects opioid blockade design was used.…”