Researchers Haggai Sharon

Researchers Haggai Sharon, Adi Maron-Katz, Eti Ben Simon, Yuval Flusser, Talma Hendler, Ricardo Tarrasch, and Silviu Brill aimed to examine whether mindfulness meditation-induced analgesia involves endogenous opioids. Previous studies supported the advantageous effects that mindfulness meditation had on pain perception (Zeidan et al., 2011). However, the mechanisms behind the meditation-induced analgesia had not been adequately studied or understood (Sharon et al., 2016). Sharon's research team sought to expand on this researchthey sought to uncover the underlying neural mechanisms by using an opioid blocker to investigate the involvement of endogenous opioids on the meditation-induced analgesia effect. If endogenous opioids were involved, they further aimed to examine whether the analgesia effects could be manipulated by suggestion or expectation through use of a placebo (Sharon et al., 2016).

The experiment was designed to consist of 15 healthy and experienced mindfulness meditation practitioners that would participate in 30 sessions of the study (Sharon et al., 2016). It was a double-blind, randomized, placebo-controlled, crossover study (Sharon et al., 2016). All chosen participants practiced sitting meditation and had reported an hour of practice at least three times a week with over a year of experience (Sharon et al., 2016). They had no neurological or psychological disorders, nor any issues with chronic pain (Sharon et al., 2016). To obtain a baseline, all subjects were initially asked to rate the pain and unpleasantness of a cold stimulus prior to any meditation. The cold stimulus used throughout the study required participants to immerse a hand in icy water for 10 seconds (Sharon et al., 2016). A visual analog scale was utilized to measure pain intensity (Sharon et al., 2016). After a normal meditation session, participants again rated the pain and unpleasantness of a cold stimulus. The subjects were then randomized to receive either 0.1 mg/kg of naloxone or saline via an intravenous line (Sharon et al., 2016).

Naloxone is an antagonist drug that competitively binds to opioid receptors (U.S. Department of Health & Human Services). After receiving the naloxone or saline, they meditated again, and then rated the pain and unpleasantness of the cold stimulus again. On another day, each subject repeated the procedure, having again been randomly assigned either the naloxone or saline (Sharon et al., 2016).
The results of the experiment found a significant reduction in pain and unpleasantness scores after natural mindfulness meditation when compared with the baseline scores (Sharon et al., 2016). There was also a significant reduction in pain and unpleasantness scores after placebo administration, but not after naloxone administration (Sharon et al., 2016). The researchers tested the correlation between the differences in pain scores following the naloxone vs placebo and participants' mindfulness-mediation experience (Sharon et al., 2016). The results clearly indicated a positive correlation of the response to intervention with years of experience (Sharon et al., 2016). Saline was more likely to reverse the induced analgesic effect in less experienced subjects, meaning they were more sensitive to the placebo. More experienced subjects had a reduced response to the placebo.

The researchers concluded that their results concurred with previous findings that mindfulness meditation produces an analgesic effect. They also believed their results to be significant because they revealed for the first time that such effects are reversible by an opioid antagonist (Sharon et al., 2016). Sharon's research team also concluded that these results indicate mindfulness meditation must involve the physiological recruitment of endogenous opioid systems (Sharon et al., 2016). Their results also suggested that with increasing experience in meditation comes a reduced response to cognitive manipulation (Sharon et al., 2016). These results reveal that mindfulness meditation evolves and will becomes less susceptible to manipulation with time and experience. Future researchers can further investigate the possibility that long-term mindfulness meditation exercise could help mediate acute or chronic pain in affected individuals. If proven effective, mindfulness meditation could have a significant impact on the estimated 11% to 40% of adults in the United States suffering from chronic pain (Dahlhamer et al., 2018).

Sharon and his team designed a well thought out experiment and reported significant findings. Their results confirmed previous findings and revealed new insight into the neurological mechanisms behind meditation-induced analgesia. The researchers conducted their experiment as a double-blind, randomized, placebo-controlled, crossover study. This enabled them to avoid bias from both the experimenters and the participants. It also kept the randomizations balanced and reduced carry-over and order effects. Overall, the results are a promising insight into the potential of mindfulness meditation in pain relief and provide a great reference point for future clinical research.

While this study was carefully planned, there were numerous and significant limitations. In order to control for individual differences in pain perception, it was practical for the study to be a within-subjects experiment; however, any within-subjects experiment carries the issues of practice effects and history effects. Gender was not accounted for in this study. Therefore, the researchers did not consider the plausible biological and psychological sex differences in pain (Bartley & Fillingim, 2013). Only 14 subjects were analyzed, and this relatively small sample size could have influenced the research outcomes. A larger sample size would have been preferable. For example, a study from 2016 that studied the effects of mindfulness-based stress reduction (MBSR) in adults with chronic low back pain enrolled 342 participants in their study (Cherkin et al., 2016).

Another limitation was that all study participants were experienced, were recruited from the same meditation practice center, and practiced the same type of sitting mindfulness meditation (Sharon et al., 2016). The results of this experiment cannot be generalized to other types of mindfulness meditation or to inexperienced patients. In 2016, researchers at Wake Forest School of Medicine studied the responses the 78 healthy adult volunteers to heat pain after 4 days of mindfulness-based mental training (Zeidan et al., 2016). The methods of this experiment were nearly identical to those of Sharon's study but used meditation-na??ve participants instead of experienced practitioners, and a heat stimulus rather than a cold one (Zeidan et al., 2016). A few other details were also adjusted, including employing a higher naloxone dose. Zeidan's study generated dramatically different results than Sharon's study. While the natural mindfulness meditation also reduced pain and unpleasantness scores, the higher dose of naloxone did not reverse the mindfulness meditation-induced analgesia as it had in Sharon's study. During naloxone administration, the pain and unpleasantness scores remained almost completely unaltered (Zeidan et al., 2016).

Zeidan and his research team concluded that the pain relief produced by mindfulness mediation was independent of endogenous opioid mechanisms (Zeidan et al., 2016). Zeidan's findings raise questions about the reproducibility of Sharon's results and the potential therapeutic implications for patients suffering from pain. Finally, this study included only healthy volunteers. Therefore, it cannot be determined whether the observations would remain valid in patients that suffer from acute or chronic pain. Sharon and his team yielded that this would be a particular concern for patients that had previously been exposed to exogenous opioids (Sharon et al., 2016).

While there is little doubt about the benefits of mindfulness practice in cognitive and emotional brain processes, substantially more research needs to be conducted before the effects on sensory pathways can be adequately understood. Despite the study's limitations, the therapeutic implications of Sharon and his team's findings could be life-altering for the many people worldwide suffering from acute or chronic pain. These findings could also prove beneficial for those addicted to exogenous opioids. Opioid drugs carry significant risks, even when prescribed and properly used. Theoretically, a meditation-induced pain relief treatment could reduce opioid abuse rates and help treat addicts. However, with inconsistent findings about the role of the endogenous opioid system, future research must validate the results before our understanding of meditation's analgesic effects can be successfully applied.

Cite this page