Recent evidence supports the beneficial effects of mindfulness meditation on pain. However, the neural mechanisms underlying this effect remain poorly understood. We used an opioid blocker to examine whether mindfulness meditation-induced analgesia involves endogenous opioids.
Methods
Fifteen healthy experienced mindfulness meditation practitioners participated in a double-blind, randomized, placebo-controlled, crossover study. Participants rated the pain and unpleasantness of a cold stimulus prior to and after a mindfulness meditation session. Participants were then randomized to receive either intravenous naloxone or saline, after which they meditated again, and rated the same stimulus.
Results
A (3) × (2) repeated-measurements analysis of variance revealed a significant time effect for pain and unpleasantness scores (both P <.001) as well as a significant condition effect for pain and unpleasantness (both P<.2). Post hoc comparisons revealed that pain and unpleasantness scores were significantly reduced after natural mindfulness meditation and after placebo, but not after naloxone. Furthermore, there was a positive correlation between the pain scores following naloxone vs placebo and participants’ mindfulness meditation experience.
Conclusions
These findings show, for the first time, that meditation involves endogenous opioid pathways, mediating its analgesic effect and growing resilient with increasing practice to external suggestion. This finding could hold promising therapeutic implications and further elucidate the fine mechanisms involved in human pain modulation.
Pain is a complex and multifaceted phenomenon involving sensory, cognitive, and emotional brain processes. In recent years, a growing body of research has provided support for the beneficial effects of mindfulness meditation on acute and chronic pain. Because mindfulness meditation has been shown to enhance cognitive control and improve emotion regulation, a placebo-like mechanism of top-down control involving suggestion and expectation has been proposed as enabling such meditation-induced analgesia. However, the neurofunctional and neurochemical mechanisms underlying this analgesic effect remain poorly understood. By using an opioid blocker during mindfulness-meditation modulation of a painful stimulus, we aimed to examine whether mindfulness meditation-induced analgesia is mediated via endogenous opioids, and if so, whether it is susceptible to manipulation by suggestion/expectation.
Methods
Fifteen healthy mindfulness-meditation practitioners participated in 30 sessions of a double-blind, randomized, placebo-controlled, crossover study. All participants were recruited from the same meditation practice center in Tel Aviv and had over a year’s experience of at least one hour of practice a day at least 3 times a week. All practiced sitting mindfulness meditation and referred to the type of practice that they perform as Shamatha or Vipassana meditation. All participants had no previous or current neurological or psychiatric disorders, and did not suffer from any chronic pain (constant or episodic syndromes). One subject was excluded from the analysis due to technical difficulties with the intravenous line; thus, the final analyses included 14 subjects. Participants were asked to rate the pain and unpleasantness of a cold stimulus (immersing their hand in icy water, 2°C-4°C, for 10 seconds) using a visual analog scale score prior to and after a normal mindfulness-meditation session (nonmanipulation condition). Participants were then randomized to receive either 0.1 mg/kg of intravenous naloxone, an opioid antagonist, or intravenous saline, after which they meditated again, and then rated the same painful stimulus. On a different date (a mean of 7 days apart), each participant underwent the same procedure in a crossover-counterbalanced design. The study was reviewed and approved by the Tel Aviv Medical Center Ethics
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-Haggai Sharon, MD, Adi Maron-Katz, MSc, Eti Ben Simon, MSc, Yuval Flusser, BA, Talma Hendler, MD, PhD, Ricardo Tarrasch, PhD, Silviu Brill, MD
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This article originally appeared in the July 2016 issue of The American Journal of Medicine.
