Neurophysiological Evidence for Remediation of Reward Processing Deficits in Chronic Pain and Opioid Misuse Following Treatment with Mindfulness-Oriented Recovery Enhancement
A new and important research study from my lab was recently accepted for publication in the respected Journal of Behavioral Medicine. This paper, which I wrote with my colleagues Brett Froeliger, Ph.D., and Matthew Howard, Ph.D., describes neurophysiological findings from a pilot randomized controlled trial (RCT) of Mindfulness-Oriented Recovery Enhancement (MORE) for chronic pain patients who had been prescribed long-term opioids for pain management. To my knowledge, this exploratory study is the first in the scientific literature to demonstrate that a mindfulness-based intervention can increase electroencephalographic (EEG) responses to natural, healthy pleasures in life.
In this study, individuals suffering from various chronic pain conditions were randomly assigned to participate in MORE or a social support group led by a therapist. Participants in the MORE group received 8 weeks of instruction in applying mindfulness-oriented techniques to alleviate pain and craving while strengthening positive emotions and the sense of reward and meaning in life. This latter aspect of MORE may be critically important. A large body of research suggests that as chronic pain and addiction progresses, people may become less physiologically responsive to natural pleasure. As their brains become less sensitive to naturally-rewarding experiences, they get less enjoyment out of life. In the absence of positive feelings, they suffer worse from emotional and physical pain, and ultimately may feel compelled to take drugs (such as opioids) to achieve a normal sense of well-being.
To enhance the sense of reward in life, participants were taught a mindful savoring practice, which involved focusing attention intensely on the sensory features (e.g., sight, sound, smell, or touch) of a pleasant experience or object (e.g., a beautiful nature scene like a sunset or the feeling of connection with a loved one) while noticing, appreciating, and absorbing any positive emotions arising in response to the pleasant event. For example, in one meditation session, participants were taught to mindfully focus on the colors, textures, and scents of a bouquet of fresh flowers, and to absorb and appreciate the emotions of contentment and joy arising from this savoring practice. Participants were asked to practice savoring in everyday life as part of a weekly homework assignment (along with a daily practice of mindful breathing meditation).
Although people tend to savor beauty naturally, we hoped that training in MORE could enhance savoring, and thereby increase the sensitivity of the brain to naturally-rewarding experiences. As an indicator of this enhanced savoring ability, we hypothesized that MORE would increase brain responses to images representing such positive experiences. To measure this in the lab, we used a computer to present participants with a series of positive photos representing naturally-rewarding objects and events (e.g., smiling babies, beautiful nature scenes, intimate couples in love) and a series of neutral photos (e.g., kitchen items, household objects, neutral faces) presented for 6 seconds each. During this task, we measured EEG brain activity at the scalp (the parietal site Pz) that were time-locked to the onset of the image. We were particularly interested in the component of the EEG known as the late positive potential (LPP), a brain response that tends to occur between 400 – 1000 ms after an emotional image is displayed. The LPP is known to be enhanced to positive images relative to neutral images in healthy individuals, whereas opiate addicts show reduced EEG brain responses to positive images (Lubman et al., 2008; 2009). In addition to measuring brain activity, we also asked participants to rate how positive they felt after viewing each photograph, and how much they desired or craved opioids in general.
In line with our hypothesis, we found that relative to the control group, MORE significantly increased the LPP brain activity to positive images relative to neutral images. In other words, participants showed enhanced brain responses while viewing naturally-rewarding stimuli following treatment with MORE. In addition, patients who exhibited the largest increases in LPP brain response to positive images experienced the greatest increases in positive emotions while viewing those images. Also, individuals who experienced the biggest increases in brain response to positive images experienced the greatest reduction in craving for opioids. These findings are important because they suggest 1) that MORE may help people to become more sensitive to naturally-rewarding objects and events, and 2) as people learn to experience greater pleasure from healthy and meaningful experiences in life, they may feel less of a need to take addictive drugs.
My colleagues and I recently advanced a neurocognitive model that suggests that MORE may alter the function of the mesocorticolimbic dopamine system, and in particular, target activity in the ventral striatum, a brain structure involved in experiencing both natural pleasure and pleasure associated with drug use. Numerous studies have shown that the ventral striatum functions abnormally in people suffering from addiction. MORE may restore normal function in this brain area, although studies using functional magnetic resonance imaging (fMRI) are needed to test this hypothesis.
Taken together, results from this new study, in combination with my previously published findings on cardiac-autonomic responses to positive stimuli, suggest that MORE may ameliorate deficits in natural reward processing among chronic patients taking long-term opioids by strengthening their ability to pay attention to healthy objects and events. Restoration of the ability to extract a sense of reward, fulfillment, and meaning out of everyday pleasures may be crucial to the ability to self-generate positive emotions and to resilience itself (Garland, Fredrickson, et al., 2010). More rigorous and larger-scale research is needed to test my hypothesis that focusing one’s attentional lens to more richly process the pleasurable, interesting, and meaningful experiences in life may make the painful and dissatisfying ones insignificant by comparison.